Two disulfide-reducing pathways are required for the maturation of plastid c-type cytochromes in Chlamydomonas reinhardtii.

In plastids, conversion of light energy into ATP relies on cytochrome f, a key electron carrier with a heme covalently attached to a CXXCH motif. Covalent heme attachment requires reduction of the disulfide-bonded CXXCH by CCS5 and CCS4. CCS5 receives electrons from the oxidoreductase CCDA, while CCS4 is a protein of unknown function. In Chlamydomonas reinhardtii, loss of CCS4 or CCS5 yields a partial cytochrome f assembly defect. Here, we report that the ccs4ccs5 double mutant displays a synthetic photosynthetic defect characterized by a complete loss of holocytochrome f assembly. This defect is chemically corrected by reducing agents, confirming the placement of CCS4 and CCS5 in a reducing pathway. CCS4-like proteins occur in the green lineage, and we show that HCF153, a distant ortholog from Arabidopsis thaliana, can substitute for Chlamydomonas CCS4. Dominant suppressor mutations mapping to the CCS4 gene were identified in photosynthetic revertants of the ccs4ccs5 mutants. The suppressor mutations yield changes in the stroma-facing domain of CCS4 that restore holocytochrome f assembly above the residual levels detected in ccs5. Because the CCDA protein accumulation is decreased specifically in the ccs4 mutant, we hypothesize the suppressor mutations enhance the supply of reducing power through CCDA in the absence of CCS5. We discuss the operation of a CCS5-dependent and a CCS5-independent pathway controlling the redox status of the heme-binding cysteines of apocytochrome f.

An unusual active site architecture in cytochrome c nitrite reductase NrfA-1 from Geobacter metallireducens.

Dissimilatory nitrate reduction to ammonia (DNRA) is a central pathway in the biogeochemical nitrogen cycle, allowing for the utilization of nitrate or nitrite as terminal electron acceptors. In contrast to the competing denitrification to N2, a major part of the essential nutrient nitrogen in DNRA is retained within the ecosystem and made available as ammonium to serve as a nitrogen source for other organisms. The second step of DNRA is mediated by the pentahaem cytochrome c nitrite reductase NrfA that catalyzes the six-electron reduction of nitrite to ammonium and is widely distributed among bacteria. A recent crystal structure of an NrfA ortholog from Geobacter lovleyi was the first characterized representative of a novel subclass of NrfA enzymes that lacked the canonical Ca2+ ion close to the active site haem 1. Here, we report the structural and functional characterization of NrfA from the closely related G. metallireducens. We established the recombinant production of catalytically active NrfA with its unique, lysine-coordinated active site haem heterologously in Escherichia coli and determined its three-dimensional structure by X-ray crystallography to 1.9 Å resolution. The structure confirmed GmNrfA as a further calcium-independent NrfA protein, and it also shows an altered active site that contained an unprecedented aspartate residue, D80, close to the substrate-binding site. This residue formed part of a loop that also caused a changed arrangement of the conserved substrate/product channel relative to other NrfA proteins and rendered the protein insensitive to the inhibitor sulphate. To elucidate the relevance of D80, we produced and studied the variants D80A and D80N that showed significantly reduced catalytic activity.

Ursolic acid in / 临床肝胆病杂志

Objective To investigate the inhibitory effect of ursolic acid in Hippophae rhamnoides L. on hepatocyte apoptosis in rats with alcoholic liver disease based on the mitochondria-cytochrome c pathway. Methods A total of 50 specific pathogen-free male Wistar rats were divided into normal control group, alcohol model group, and low-, middle-, and high-dose ursolic acid groups using a random number table, with 10 rats in each group. The rats in the normal control group were given normal saline by gavage once a day for 8 weeks; the rats in the alcohol model group were given alcohol at increasing concentrations by gavage for 8 consecutive weeks; the rats in the low-, middle-, and high-dose ursolic acid groups were given ursolic acid at a dose of 50, 100, and 150 mg/kg, respectively, followed by an equal volume of alcohol as the model group 1 hour later. Serum liver function parameters were measured for each group; HE staining was used to observe liver histopathology; an electron microscope was used to observe hepatocyte ultrastructure; the TUNEL method was used to measure hepatocyte apoptosis; Western Blotting was used to measure the protein expression levels of cytochrome c and activated caspase-3 in hepatocyte mitochondria and cytoplasm. A one-way analysis of variance was used for comparison of continuous data between multiple groups, and the least significant difference t -test was used for further comparison between two groups. Results Compared with the alcohol model group, the middle- and high-dose ursolic acid groups had significant reductions in the serum level of alanine aminotransferase, aspartate aminotransferase, and cholinesterase (all P < 0.05). The rats in the alcohol model group had disordered arrangement of hepatic cords with marked hepatocyte edema and fatty degeneration, while those in the middle- and high- dose ursolic acid groups had basically normal arrangement of hepatic cords and a significant improvement in hepatocyte fatty degeneration, as well as a significant increase in the number of hepatocyte mitochondria and a significant improvement in morphology. Compared with the alcohol model group, the middle- and high-dose ursolic acid groups had significantly lower hepatocyte apoptosis rate and protein expression levels of cytochrome c and caspase-3 in cytoplasm (all P < 0.05). Conclusion Ursolic acid in Hippophae rhamnoides L. can improve the liver function and histomorphology of rats with alcoholic liver disease, possibly by inhibiting the release of cytochrome c in hepatocyte mitochondria, the activation of caspase-3, and the apoptosis of hepatocytes via the mitochondria-cytochrome c pathway.

Effects of moxibustion at bilateral Feishu (BL13) and Xinshu (BL15) combined with benazepril on myocardial cells apoptosis index and apoptosis-related proteins cytochrome c and apoptosis-inducing factor in rats with chronic heart failure.

OBJECTIVE: To observe the effects of moxibustion at bilateral Feishu (BL13) and Xinshu (BL15) combined with benazepril on myocardial cells apoptosis index, the expression levels of apoptosis-related proteins cytochrome c (Cyt-C) and apoptosis-inducing factor (AIF) in chronic heart failure (CHF) rats. METHODS: Sixty-five rats were randomly divided into normal group () and model-I group (). After modeling, CHF rats in model-I group were divided into model group, moxibustion group, benazepril group, moxibustion plus benazepril group (abbreviated as aibei group, the same below), 10 rats in each group. Echocardiogram index was examined by echocardiography. Hemodynamic indices were measured by rat cardiac function meter. Serum B-type brain natriuretic peptide (BNP) was detected by enzyme-linked immunosorbent assay. Myocardial cells apoptosis index was detected by terminal-deoxynucleoitidyl transferase mediated nick end labeling staining. Pathological changes of myocardial tissues were observed by hematoxylin and eosin staining. The expression levels of Cyt-C and AIF in myocardial tissues were detected by Western blot. RESULTS: Compared with normal group, ejection fraction and left ventricular diameter shortening rate in model-Ⅰ group were significantly reduced, myocardial cells of rats in model group exhibited unclear transverse striations, cells swellings and vacuoles, cardiac functions were deteriorated, serum BNP level, myocardial cells apoptosis index, and the expression levels of Cyt-C and AIF were significantly increased. Compared with model group, myocardial cells of rats in moxibustion group, benazepril group, and aibei group were dyed more evenly, muscle fibers were arranged relatively neatly, cardiac functions were improved, serum BNP level, myocardial cells apoptosis index, and the expression levels of Cyt-C and AIF were significantly decreased. Compared with aibei group, cardiac functions were worsened, myocardial cells apoptosis index, and the expression levels of Cyt-C and AIF were increased. CONCLUSION: Moxibustion at bilateral Feishu (BL13) and Xinshu (BL15) combined with benazepril could improve CHF better than moxibustion at bilateral Feishu (BL13) and Xinshu (BL15) or benazepril alone. The mechanisms might be that they can inhibit the expressions of Cyt-C and AIF, and inhibit the apoptosis of cardiomyocytes.

Changes and clinical significance of autophagy-related proteins Beclin-1 and cytochromes C in patients with hand, foot and mouth disease / 中华微生物学和免疫学杂志

Objective:To investigate the expression and clinical significance of Beclin-1 and cytochromes C (CytC) in patients with hand, foot and mouth disease (HFMD).Methods:Sixty children with HFMD were classified into two groups of severe group and common group with 30 cases in each group. Another thirty children who underwent circumcision and had no underlying disease were selected as control group. Serum Beclin-1, CytC and S100B levels were detected before and after treatment. The levels of Beclin-1 and CytC in cerebrospinal fluid (CSF) of children with severe HFMD were detected before and after treatment. Receiver operating characteristic (ROC) curve was used to evaluate the prediction efficiency of Beclin-1 and CytC for the severity of HFMD.Results:Serum Beclin-1 and CytC levels in the severe group were higher than those in the other two groups ( P<0.01), and the common group showed significantly increased serum Beclin-1 and CytC levels as compared with the control group ( P<0.01). After treatment, the serum Beclin-1 and CytC levels decreased in both severe and common groups ( P<0.05). Compared with the common group, the severe group had remarkable increases in the levels of Beclin-1 and CytC in CSF ( P<0.01), which decreased significantly after treatment ( P<0.01). Serum Beclin-1 and CytC levels were positively correlated with the level of S100B protein. In the prediction of severe HFMD, serum CytC had the highest Youden value of 0.533 at the cut-off value of 38.785 ng/ml with a sensitivity of 56.67% and a specificity of 96.67%; serum Beclin-1 had the highest Youden value of 0.467 at the cut-off value of 6.560 ng/ml with a sensitivity of 46.67% and a specificity of 100.00%. Combined measurements of these two parameters had the highest predictive value for severe HFMD with a sensitivity of 76.67% and a specificity of 96.67%. Conclusions:Serum Beclin-1 and CytC levels were conducive to predict the severity and treatment outcomes of HFMD. Combined measurements of these two parameters had a higher predictive value for severe HFMD.

Electrons selective uptake of a metal-reducing bacterium Shewanella oneidensis MR-1 from ferrocyanide.

The extracellular electron transfer of Shewanella oneidensis MR-1 (MR-1) has been extensively studied due to the importance of the biosensors and energy applications of bioelectrochemical systems. However, the oxidation of metal compounds by MR-1, which represents the inward extracellular electron transfer from extracellular electron donors into the microbe, is barely understood. In this study, MR-1 immobilized on an electrode electrocatalyzes the oxidation of [Fe(CN)6]4- to [Fe(CN)6]3- efficiently and selectively. The selectivity depends on midpoint potential and overall charge(s) of redox molecules. Among 12 investigated redox molecules, the negatively charged molecules with high midpoint potentials, i.e., [Ru(CN)6]4- and [Fe(CN)6]4-, show strong electrocatalysis. Neither reference bacteria (Escherichia coli K-12 nor Streptococcus mutans) electrocatalyze the oxidation of [Fe(CN)6]4-. The electrocatalysis decays when MR-1 is covered with palladium nanoparticles presumptively involved with cytochromes c. However, cytochromes c MtrC and OmcA on MR-1 do not play an essential role in this process. The results support a model that [Fe(CN)6]4- donor electrons to MR-1 by interacting with undiscovered active sites and the electrons are subsequently transferred to the electrode through the mediating effect of [Fe(CN)6]4-/3-. The selective electron uptake by MR-1 provides valuable and fundamental insights of the applications of bioelectrochemical systems and the detection of specific redox molecules.

Mixture of ginkgolide A and ginkgolide B inhibits JNK apoptosis pathway in neurons of rats with permanent middle cerebral artery occlusion / 第二军医大学学报

Objective To investigate the protective effect of ginkgolide A and ginkgolide B (GKAB) mixture on neurons of rats with permanent middle cerebral artery occlusion (pMCAO) and related molecular mechanisms. Methods Sixty male Sprague-Dawley rats were randomly divided into sham group, pMCAO permanent focal cerebral ischemia group and GKAB-treated low-, medium- and high-dose groups. In addition to the sham group (only isolated without interruption of the arteries), the rats in the remaining four groups were induced pMCAO by blocking the right middle cerebral artery. Rats in the GKAB-treated low-, medium- and high-dose groups were injected with GKAB 12.5, 25, and 50 mg/kg through sublingual vein at 10 min after pMCAO, while the sham and pMCAO groups were injected with saline of the same volume as the medium-dose group. After 12 h of treatment, the neuronal apoptosis was determined by TUNEL method, the level of phosphorylated c-Jun N-terminal kinase (p-JNK) was determined by immunohistochemistry, the expressions of p-JNK, Bcl-2, Bax, cytochrome C (Cyt C), caspase-9, caspase-3, cleaved caspase-9, and cleaved caspase-3 in brain tissues were detected by Western blotting. Results Compared with the sham group, the apoptosis rate and p-JNK expression of neurons in the pMCAO group were significantly increased (P<0.01), and the expressions of apoptosis-related proteins Bax, cleaved caspase-9 and cleaved caspase-3 in brain tissues were significantly increased (P<0.01), while the expressions of Bcl-2, caspase-9 and caspase-3 in brain tissues were significantly decreased (P<0.01). Compared with the pMCAO group, the apoptosis rate and p-JNK expression of neurons in GKAB-treated low-, medium- and high-dose groups were significantly decreased (P<0.01), the expressions of Bax, cleaved caspase-9 and cleaved caspase-3 protein were significantly decreased (P<0.01), and the expressions of Bcl-2, caspase-9 and caspase-3 were significantly increased (P<0.01) in a dose-dependent manner. Compared with the sham group, the expression of Cyt C in cytoplasm in the pMCAO group was significantly increased, and the expression of mitochondrial Cyt C was significantly decreased (P<0.01). Compared with the pMCAO group, the expressions of Cyt C in cytoplasm in the GKAB-treated low-, medium- and high-dose groups were significantly decreased in a dose-dependent manner, and the expressions of mitochondrial Cyt C were significantly increased (P<0.05, P<0.01). Conclusion GKAB can inhibit neuronal apoptosis after pMCAO in rats, and its mechanism may be related to the inhibition of JNK phosphorylation and JNK signaling pathway and the block of mitochondrial apoptosis pathway.

Effects of medicated serum containingDuhuojisheng Decoction on the expression of cytochrome C, proCaspase-9 and proCaspase-3 in degenerative chondrocytes / 中国组织工程研究

BACKGROUND:Previous studies have shown that apoptosis, a central feature of articular chondrocytes, plays a dominant role in cartilage damage, which is one of the pathological factors of articular cartilage degeneration. OBJECTIVE:To observe the effects of meditcated serum containingDuhuojisheng Decoction on the expression of cytochrome C, proCaspase-9 and proCaspase-3 in rat degenerative chondrocytes in vitro and to investigate the possible molecular biological mechanism ofDuhuojisheng Decoction in the treatment of knee osteoarthritis. METHODS:A cultivation system of degenerative chondrocytes in vitro was established. After treatment with meditcated serum containingDuhuojisheng Decoction or blank serum for 24 and 48 hours, the protein expression of cytochrome C, proCaspase-9 and proCaspase-3 was measured by western blot assay. RESULTS AND CONCLUSION: In the cytoplasm, the release of cytochrome C was reduced gradualy in both groups in a time-dependent manner, and the release amount of cytochrome C was significantly lower in the medicated serum group than the blank serum group (P < 0.05). In mitochondria, cytochrome C leakage was gradualy decreased in both groups, and it was decreased significantly in the medicated serum group compared with the blank serum group (P < 0.05). The protein expression of proCaspase-9 and proCaspase-3 was gradualy increased in both groups, especialy in the medicated serum group; the medicated serum containingDuhuojisheng Decoction could promote the protein expression of proCaspase-9 and proCaspase-3 in a time-dependent manner, and there was a significant difference at 24 and 48 hours (P< 0.01). These findings indicate that the medicated serum containingDuhuojisheng Decoction can inhibit the apoptosis of osteoarthritis chondrocytes through inhibiting the release of cytochrome C and the activation of Caspase-9 and Caspase-3.

Effects of inhibition of adenosine monophosphate -activated protein kinase on expressions of cytochrome c and caspase-3 and neuronal apoptosis in the cerebral cortex after cerebral ischemia-reperfusion injury in mice / 国际脑血管病杂志

Objective To investigate the effects of inhibition of adenosine monophosphate -activated protein kinase (AMPK) on expressions of cytochrome c (CytC) and caspase -3 and apoptosis in the cerebral cortex after cerebral ischemia-reperfusion injury in mice. Methods Thirty-six male C57BL/6 mice w ere randomly divided into three groups, a sham operation group, a ischemia -reperfusion group, and a AMPK inhibitor group, 12 in each group. A model of middle cerebral artery occlusion w as induced by suture method. The AMPK inhibitor compound C ( 20 mg/kg) w as injected intraperitonealy in the AMPK inhibitor group, the equal volume normal saline w as injected intraperitonealy in the sham operation group and the ischemia-reperfusion group w hen a thread w as inserted. Immunohistochemical staining w as used to detect the expression levels of CytC and caspase-3 and TUNEL method w as used to detect apoptosis at 24 h after ischemia-reperfusion. Results Compared w ith the ischemia-reperfusion group, the numbers of CytC (28.86 ±9.65/HP vs.58.86 ±9.65/HP; t = 7.615, P = 0.030 ) and caspase-3 (7.16 ±5.85/HP vs. 14.36 ±7.85/HP; t =2.548, P =0.035), and TUNEL (67.14 ±8.55/HP vs.95.00 ±13.51/HP; t = 6.891, P = 0.030) positive cels in the cerebral cortex w ere reduced significantly in the AMPK inhibitor group. Conclusion Inhibition of AMPK activity after cerebral ischemia-reperfusion may decrease apoptosis by dow nregulating the expressions of CytC and caspase -3, and play a neuroprotective effect.

The Protective Effect of Ebselen on Mitochondrial Damage after Spinal Cord Injury in Rats / 天津医药

Objective To investigate the protective effect of Ebselen on mitochondrial damage and its influence to Cytochrome C expression and the neuronal apoptosis after spinal cord injury in rats. Methods Sixty adult SD rats were ran-domly divided into 5 groups (12 each group). Spinal cord injury model was made using Allen's method. Sham operation group received only laminectomy;SCI group received laminectomy and spinal trauma;Saline group received saline injection intraperitoneally (0.1%DMSO) after injury;methylprednisolone group received 30 mg/kg methylprednisolone injection intra-peritoneally, ebselen group received 10 mg/kg ebselen injection intraperitoneally. The malonaldehyde (MDA) and glutathi-one (GSH)level at the injured sites of the spinal cord were detected 24 hours after trauma, and the expression level of Cyto-chrome C was also observed. Finally, neuronal apoptosis was identified by TUNEL staining. Results MDA level in the Eb-selen group was significantly lower than that in the SCI group, and GSH level was significantly elevated in the Ebselen group compared with SCI group (P<0.01). Expression of Cytochrome C in Ebselen group was lower than that in SCI group shown by Western blot, and the neuronal apoptosis in Ebselen group reduced significantly too compared with SCI group (P<0.01). Conclusion Ebselen can alleviate peroxidation,prohibit expression of Cytochrome C and inhibit neuronal apoptosis,thus it shows a protective effect to experimental acute SCI.

Mechanism for Protective Effects of Selective Mitochondrial Fission Inhibitor on Neurons after Acute Spinal Cord Injury in Rats / 天津医药

Objective To detect the effects of the selective mitochondrial fission inhibitor-Mdivi-1 on the malondi-alolehyde (MDA), glutathione (GSH) as well as cytochrome C (Cyt-C) in neuronal mitochondria and neuronal apoptosis. Methods Thirty-six adult female SD rats (250-300 g) were randomly divided into 3 groups (n=12):sham operation (Sham) group, single spinal cord injury (SCI) group and Mdivi-1 pretreatment (1.20 mg/kg, Mdivi-1) group. In sham group, the rats’ spinal cord was exposed, but no hit. The rat model of spinal cord injury was established by Allen’s method in SCI group and Mdivi-1 group. In Mdivi-1 group, rats were given Mdivi-1 through the tail vein 15 min before spinal cord injury, and SCI group received the same amount of dimethyl sulfoxide (DMSO). Rats in Sham group were sacrificed 8 h after exposing spinal cord. Rats in SCI group and Mdivi-1 group were sacrificed at 8 h after the spinal cord injury, then were removed the spinal cord T9-11. The contents of MDA and GSH in mitochondria of spinal cord tissues were detected with spectrophotometer. The expressions of Cyt-C protein in the mitochondria and cytoplasm were detected by Western blot assay. The neuronal apoptosis was assessed by TUNEL staining. Results Compared with Sham group, levels of Cyt-C and GSH in mitochondria were decreased significantly (P<0.01), while levels of MDA in mitochondria, Cyt-C in cytoplasm and the neuronal apopto-sis were increased significantly in SCI group (P<0.01). Compared with SCI group, Cyt-C and GSH levels in mitochondria were increased significantly in Mdivi-1 group (P<0.01), however, MDA in mitochondria,Cyt-C in cytoplasm and the neuro-nal apoptosis were significantly reduced (P<0.01). Conclusion Mdivi-1 can relieve neurons from mitochondrial oxidative damage, inhibit the release of cytochrome C and neuronal apoptosis after acute spinal cord injury, which plays a role in pro-moting the recovery of spinal cord function.

Study on mechanism of mitochondrial in K562/G01 cells apoptosis induced by triptolide / 白血病·淋巴瘤

Objective To investigate the possible mechanism of mitochondrial in chronic myeloid leukemia cells K562/G01 cells apoptosis induced by triptolide.Methods K562/G01 cells were treated with different concentrations of triptolide.MTT assay was used to assess cytotoxic effect.FCM was used to determine apoptosis rate,mitochondrial membrane potential and the activity of Caspase-9 of each experimental group.Real-time quantitative PCR assay was used to quantify mRNA levels of Caspase-9 and cytochrome C and Western blot assay was used to determine protein levels of cytochrome C.Results Triptolide inhibited the growth and proliferation of K562/G01 cells in a time-and dose-dependent manner (both P ＜ 0.001).Meantime,triptolide could make the mitochondria membrane potential fade away and enhance the activity of Caspase-9 (F =566.431,2 555.485,P ＜ 0.001).In addition,triptolide could dose-dependently up-regulated the transcription of Caspase-9 and cytochrome C (F =61 007.702,452 121.760,P ＜ 0.001),and the protein expression of cytochrome C,whose gray value in each experimental group was 21.54±0.59,39.63±0.58,53.29± 1.47 and 75.68±1.87 (F =5 677.928,P ＜ 0.001) respectively.Conclusion Triptolide could potently inhibit the growth and proliferation of K562/G01 cells,and the mitochondria apoptosis pathway might be one of the important apoptosis mechanisms in chronic myeloid leukemia cells induced by triptolide.

Effect of Hydrogen Peroxide on Free Mitochondrial Cytochrome-c Release / 天津医药

Objective To investigate the effect of hydrogen peroxide (H2O2) pretreatment on free mitochondrial cyto-chrome c (Cyt-c) release in mitochondrial levels, and reveal the mechanism of the ischemic preconditioning (IPC) on the ischemia reperfusion (IR) injury thereof. Methods The rat liver mitochondria was isolated and made free mitochondria. Free mitochondria were divided into 5 groups:control group (C) and different concentrations of Ca2+groups (12.5, 25, 50 and 100 μmol/L). The levels of Cyt-c and second mitochondria-defived activator of caspase (Smac) were detected after 10 min stimulation of free mitochondria. The free mitochondrial IPC reperfusion model was made and divided into seven groups:C group, IR group and different concentrations of H2O2 groups (2 μL H2O2 in 200 μL system respectively, final concentration of 1, 2, 5, 20 and 100 μmol/L respectively). 100 μmol/L Ca2+was used again on the simulation of IR group. The level of Cyt-c release was detected. The changes in the activity of cardiolipin were detected in IR group and H2O2 (1 and 2 μmol/L of final concentration) groups.Results Compared with C group, there were significantly higher levels of Cyt-c and Smac emission in 25, 50, and 100 μmol/L Ca2+groups (P<0.05). Compared with IR group, there was significantly decreased level of Cyt-c emission in H2O2 (1 and 2 μmol/L) groups (P < 0.05). The activity of cardiolipin was changed when reducing release of Cyt-c. Conclusion Cyt-c was bonded with cardiolipin more closely when the low concentration of H2O2 pretreatment in mitochondria. There was a lower level of Cyt-c emission in mitochondria after stimulation with high concentration of Ca 2+(100 μmol/L Ca2+). The blocking apoptotic pathway plays a key fact in the effect of IPC on IR injury.

Structural characterization of nitrosomonas europaea cytochrome c-552 variants with marked differences in electronic structure.

Nitrosomonas europaea cytochrome c-552 (Ne c-552) variants with the same His/Met axial ligand set but with different EPR spectra have been characterized structurally, to aid understanding of how molecular structure determines heme electronic structure. Visible light absorption, Raman, and resonance Raman spectroscopy of the protein crystals was performed along with structure determination. The structures solved are those of Ne c-552, which displays a "HALS" (or highly anisotropic low-spin) EPR spectrum, and of the deletion mutant Ne N64Δ, which has a rhombic EPR spectrum. Two X-ray crystal structures of wild-type Ne c-552 are reported; one is of the protein isolated from N. europaea cells (Ne c-552n, 2.35 Å resolution), and the other is of recombinant protein expressed in Escherichia coli (Ne c-552r, 1.63 Å resolution). Ne N64Δ crystallized in two different space groups, and two structures are reported [monoclinic (2.1 Å resolution) and hexagonal (2.3 Å resolution)]. Comparison of the structures of the wild-type and mutant proteins reveals that heme ruffling is increased in the mutant; increased ruffling is predicted to yield a more rhombic EPR spectrum. The 2.35 Å Ne c-552n structure shows 18 molecules in the asymmetric unit; analysis of the structure is consistent with population of more than one axial Met configuration, as seen previously by NMR. Finally, the mutation was shown to yield a more hydrophobic heme pocket and to expel water molecules from near the axial Met. These structures reveal that heme pocket residue 64 plays multiple roles in regulating the axial ligand orientation and the interaction of water with the heme. These results support the hypothesis that more ruffled hemes lead to more rhombic EPR signals in cytochromes c with His/Met axial ligation.

Clinical study of warfarin anticoagulation effect in elderly patients based on vitamin K epoxide reductase complex 1 and cytochrome P450 2C9 genetic polymorphisms / 中华老年医学杂志

Objective To investigate the efficacy and safety of warfarin anticoagulation in Chinese elderly patients based on vitamin K epoxide reductase complex 1 (VKORC1) and cytochrome P450 2C9 (CYP2C9) genetic polymorphisms.Methods Clinical data of 41 elderly patients with initial anticoagulation therapy in our emergency department and respiratory department were collected.Patients were divided into observation group (n=20,patients treated with warfarin based on genetic polymorphisms) and control group (n =21,patients treated based on clinical experience).The international normalized ratio (INR),the time of INR stabilized within target range (2.0-3.0) and the incidence of bleeding episodes in 6-month follow up were compared between groups.Results INR within target range at day 3,4,5 and 7 were 0.0％,42.1％,52.6％,68.4％ in observation group and 0.0％,10.0％,25.0％,35.0％ in control group,respectively.There were significant differences in INR within target range at day 4,7 between the two groups (both P＜0.05),while no significant difference was found in INR within target range at day 5 (P＞0.05).The time of INR stabilized within target range was shorter in observation group than in control group [(9.5±2.4) d vs.(12.3± 4.8) d,P＜0.05].Bleeding complication occurred in 3 patients in observation group and 5 patients in control group,and there was no significant difference between the two groups.Conclusions Warfarin therapy based on VKORC1 and CYP2C9 gene polymorphisms may shorten the time of first INR reaching the target value and INR within target range in elderly patients.However,the risk of bleeding complications should be alerted.

Efficient and selective isotopic labeling of hemes to facilitate the study of multiheme proteins.

Specific isotopic labeling of hemes provides a unique opportunity to characterize the structure and function of heme-proteins. Unfortunately, current methods do not allow efficient labeling in high yields of multiheme cytochromes c, which are of great biotechnological interest. Here, a method for production of recombinant multiheme cytochromes c in Escherichia coli with isotopically labeled hemes is reported. A small tetraheme cytochrome of 12 kDa from Shewanella oneidensis MR-1 was used to demonstrate the method, achieving a production of 4 mg pure protein per liter. This method achieves, in a single step, efficient expression and incorporation of hemes isotopically labeled in specific atom positions adequate for spectroscopic characterization of these complex heme proteins. It is, furthermore, of general application to heme proteins, opening new possibilities for the characterization of this important class of proteins.

Expressions of apoptosis-related gene Bax, Bcl-2 and cytochrome C in renal tissue of streptozotocin-induced diabetic rats / 第二军医大学学报

Objective To observe the changes in expressions of apoptosis-promoting gene Bax, apoptosis-inhibiting gene Bcl-2, and cytochrome C in the renal tissue of diabetic rats. Methods Twenty-four male Sprague-Dawley rats were randomly divided into 2 groups (n=12): normal control group and diabetic group. Diabetic models were induced by single intraperitoneal injection of 2% streptozotocin (dissolved in pH 4. 4,0. 1 mol/L citric acid sodium buffer, 65 mg/kg). Normal control group was only injected with same volume of folie buffer. Animals were sacrificed at the 4th and 12th week, and body mass, 24-hour urine protein, blood glucose, blood urine nitrogen and serum creatinine were determined. The changes of the renal morphology were observed by H-E staining. Immunohistochemical method was used to investigate the expressions of Bax, Bcl-2 and cytochrome C protein. The apoptosis of renal cortex cells was determined by TUNEL method. Results Compared with normal control group, the 24-hour urine protein, blood glucose, blood urine nitrogen and serum creatinine were significantly increased in the diabetic group (P<0. 05, P<0. 01). The size of glomerulus was increased in diabetic rats during the 4th week; hyperplasia of renal glomerulus mesangial matrix, glomerular sclerosis, and vacuolar degeneration in renal tubular epithelial cells were observed during the 12th week. With disease progression in the diabetic group, the expressions of Bax and cytochrome C were increased and the expression of Bcl-2 was decreased. Apoptosis tests showed increased apoptotic cells in the 4th week, mostly in both the distant tubular epithelial cells; in the 12th week, apoptotic cells were seen in both the distant tubular and proximal tubules. Conclusion Renal expression of Bax and cytochrome C gradually increases with the progression of diabetes, inducing apoptosis of more cells and leading to renal dysfunction, which may partly contribute to the diabetic nephropathy in diabetic rats.

Effects of different time administration of propofol on cytochrome c in cytoplasm in rat hippocampal neurons with hypoxia-reoxygenation injury / 中华麻醉学杂志

ObjectiveTo investigate the effects of different time administration of propofol on cytochrome c (Cyt c) in the cytoplasm in rat hippocampal neurons with hypoxia-reoxygenation (H/R) injury.MethodsPrimary cultured hippocampal neurons were randomly divided into 5 groups ( n =5 each):control group (group C),model of H/R injury group (group M),and different time administration of propofol groups (group Ⅰ,Ⅱ,Ⅲ ).In groups M,Ⅰ,Ⅱ and Ⅲ,the neurons were exposed to 95％ N2 + 5％ CO2 for6 h followed by 12 h reoxygenation.In groups Ⅰ, Ⅱ,Ⅲ,propofol was added to the culture medium before hypoxia,immediately after reoxygenation and at 2 h of reoxygenation (T0-2) respectively,with the final concentration of 20 μmol/L.The cell apoptosis was observed at T1,2 and at 24 h of reoxygenation ( T3 ) and the concentration of Cyt c in the cytoplasm was detected at T1-3.ResultsCompared with group C,the concentration of Cyt c in the cytoplasm was significantly increased at T1-3 in group M and at T1,2 in groups Ⅰ,Ⅱ,Ⅲ (P ＜ 0.05).Compared with group M,the concentration of Cyt c in the cytoplasm was significantly decreased at T1-3 in group I and at T1,2 in groups Ⅱ and Ⅲ ( P ＜0.05).The concentration of Cyt c in the cytoplasm was significantly higher at T1,2 in groups Ⅱ and Ⅲ than in group Ⅰ,and at T2 in group Ⅲ than in group Ⅱ ( P ＜ 0.05).The neuronal apoptosis was significantly decreased in groups Ⅰ,Ⅱ and Ⅲ as compared with group M.ConclusionDifferent time administration of propofol can reduce the mitochondrial Cyt c release to the cytoplasm,inhibit apoptosis in hippocampal neurons,and reduce H/R injury in rats,with better effect when given before hypoxia.

Effects of Inula Britannica on myocardial caspase-3 and cytochrome C expression following overtraining-induced acute myocardial injury in rats / 中华麻醉学杂志

Objective To investigate the effects of Inula Britannica on myocardial caspase-3 and cytochrome c ( cyt c) following overtraining-induced acute myocardial injury in rats.Methods Forty-eight male Wistar rats weighing 200-220 g were randomly divided into 3 groups:group control (group C,n =8) ; group exhausting swim (group E,n =24) and group Inula Britannica (group IB,n =16).The animal model of overtraining-indnced acute myocardial injury was developed by exhausting swim.The animals were forced to swim until they were exhausted.The animals sank to the bottom and no righting reflex or escape response was elicited when they were taken out of water in groups E and IB.In group IB oral Inula Britannica 25 ml/kg was given 24 h and immediately before overtraining.Blood samples were taken from inferior vena cava immediately and at 6,24 h after overtraining in group E and at 6,24 h after overtraining in group IB for determination of serum cardiac troponin I (cTnI) concentration (by ELISA).The animals were sacrificed after blood sampling and myocardial specimens were obtained for microscopic examination and determination of caspase-3 and cyt c expression (by immuno-histochemistry).Results Overtraining significantly increased serum cTnI concentration and up-regulated myocardial caspase-3 and cyt c expression in group E as compared with group C.Oral Inula Britannica significantly attenuated overtraining-induced increase in serum cTnI concentration and myocardial caspase-3 and cyt c expression in group IB as compared with group E.Conclusion Inula Britannica can reduce overtraining-induced acute myocardial injury by down-regulating caspase-3 and cyt c expression.