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1.
Am J Hosp Palliat Care ; 40(10): 1098-1105, 2023 Oct.
Article in English | MEDLINE | ID: mdl-36564870

ABSTRACT

Background: An estimated 9.6 million people died from cancer globally in 2018, which is a reflection of the quality of patients' end-of-life care and its costs. Aim: To estimate direct medical costs of the last 30 days of oncology patients admitted to an inpatient clinic and to evaluate factors associated with medical costs at the end of life. Design: Cost-of-illness study with data from a retrospective cohort. Setting/Participants: We included patients aged 18 and older who were diagnosed with incurable cancer and who were admitted to a tertiary hospital in Brazil between January 1, 2018 and December 31, 2019. Results: Our sample included 109 patients with an average age of 69 (61‒76). The median overall survival was 4.3 (.9‒12.9) months. The median cost per patient per day related to hospitalization was BRL 119 (73‒181)/United States dollars [USD] 21 (13‒33). The cost of medication was BRL 66 (40‒105)/USD 12 (7‒19), representing 55.46% of costs while that of materials and supplies was BRL 30 (18‒49)/USD 5 (3‒9). In the multivariate analysis, when the limitation of interventions was recorded in the medical record, the median cost is reduced by BRL 50 (USD 9) per patient per day. Conclusions: The median cost per patient per day was BRL 119 (73‒181). The recording of limitations of therapeutic interventions in the medical record was a predictor variable that influenced the final medical cost of patients, suggesting that medical practice and decision-making in end-of-life care impact costs.


Subject(s)
Neoplasms , Humans , Aged , Retrospective Studies , Costs and Cost Analysis , Neoplasms/therapy , Hospitalization , Inpatients , Health Care Costs
2.
Nanoscale Adv ; 4(6): 1668-1680, 2022 Mar 15.
Article in English | MEDLINE | ID: mdl-36134366

ABSTRACT

Graphene is an attractive choice for the development of an effective drug carrier in cancer treatment due to its high adsorption area and pH-responsive drug affinity. In combination with the highly potent metabolic drug phenformin, increased doses could be efficiently delivered to cancer cells. This study compares the use of graphene oxide (GO) and polyethylene glycol stabilized (PEGylated) pristine graphene nanosheets (PGNSs) for drug delivery applications with phenformin. The cytotoxicity and mitotoxicity of the graphene-based systems were assessed in human cells and zebrafish larvae. Targeted drug release from GO and PGNSs was evaluated at different pH levels known to arise in proliferating tumor microenvironments. PGNSs were less cytotoxic and mitotoxic than GO, and showed an increased release of phenformin at lower pH in cells, compared to GO. In addition, the systemic phenformin effect was mitigated in zebrafish larvae when bound to GO and PGNSs compared to free phenformin, as measured by flavin metabolic lifetime imaging. These results pave the way for improved phenformin-based cancer therapy using graphene nano-sheets, where PGNSs were superior to GO.

3.
Crit Rev Oncol Hematol ; 173: 103658, 2022 May.
Article in English | MEDLINE | ID: mdl-35337971

ABSTRACT

The use of patient-reported outcomes brings direct benefits to the daily practice in Clinical Oncology, providing information that allows the monitoring of patients between consultations, with an increase in the bond with the medical team and the patient's satisfaction with their treatment. This review seeks to identify electronic systems for collecting patient data, highlighting the possible benefits that motivated the use of these systems and identifying the population, instruments, way of handling alerts and possible limitations and barriers to implementation in clinical practice. Thus, 25 articles were selected and reviewed, following a previously established systematic literature review protocol. This review is useful for gathering information for the development of new patient-focused applications in Oncology.


Subject(s)
Medical Oncology , Patient Reported Outcome Measures , Humans , Surveys and Questionnaires
4.
ACS Omega ; 6(38): 24619-24629, 2021 Sep 28.
Article in English | MEDLINE | ID: mdl-34604644

ABSTRACT

Graphene-based drug carriers provide a promising addition to current cancer drug delivery options. Increased accessibility of high-quality graphene made by plasma-enhanced chemical vapor deposition (PE-CVD) makes it an attractive material to revisit in comparison to the widely studied graphene oxide (GO) in drug delivery. Here, we show the potential of repurposing the metabolic drug phenformin for cancer treatment in terms of stability, binding, and pH-responsive release. Using covalent attachment of poly(ethylene glycol) (PEG) onto pristine (PE-CVD) graphene, we show that PEG stabilized graphene nanosheets (PGNS) are stable in aqueous solutions and exhibit higher binding affinity toward phenformin than GO. Moreover, we experimentally demonstrate an improved drug release from PGNS than GO at pH levels lower than physiological conditions, yet comparable to that found in tumor microenvironments.

5.
FEBS Open Bio ; 10(4): 495-506, 2020 04.
Article in English | MEDLINE | ID: mdl-32115900

ABSTRACT

Transglutaminases are a family of enzymes that catalyse the cross-linking of proteins by forming covalent bonds between lysine and glutamine residues in various polypeptides. Cross-linking reactions are involved in blood clots, skin formation, embryogenesis and apoptosis. Clinically, these enzymes appear to be implicated in neurodegenerative diseases, tumours and coeliac diseases. Transglutaminases have great potential for use in the food industry because of their ability to cross-link proteins that are not normally linked. Here, a gene coding for transglutaminase from Atlantic cod was cloned into a bacterial expression vector and used to transform protein expression in a strain of Escherichia coli. The successful expression of recombinant transglutaminase protein from Atlantic cod (AcTG-1) as a soluble protein upon induction at low temperature was confirmed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis, immunoblotting and mass spectrometry analysis. Biochemical characterisation demonstrated that the transglutaminase was active between 0 and 65 °C, but was completely inactivated after 20-min incubation at 70 °C. Interestingly, the enzyme displayed cold-adapted features, such as temperature instability combined with high catalytic efficiency at low temperatures (8-16 °C). In addition, the enzyme had optimal activity at 50 °C, a new feature for a cold-adapted enzyme. AcTG-1 was active in the pH range from 6 to 9, with an optimum at pH 8, and required 5 mm calcium for maximum activity. Potential calcium-binding sites in the enzyme were predictable, making the enzyme an appropriate model for studying structure-function relationships in the calcium-dependent transglutaminase family. In vitro gel analysis revealed that transglutaminase cross-linked casein, collagen and gelatin. The binding of fish fillets in the presence of recombinant AcTG-1 provided further macroscopic proof for the potential application of AcTG-1 as a biological cross-linker in the food industry. Once binding occurred, fish fillets withstood further processing such as frying, boiling, freeze-thawing and chilling. The low-temperature activity and new enzymatic properties of AcTG-1 appear to offer advantages over commercially available enzymatic glues in the food industry.


Subject(s)
Calcium/metabolism , Cold Temperature , Food Handling , Gadus morhua/metabolism , Medicine , Transglutaminases/genetics , Transglutaminases/metabolism , Adhesives/chemistry , Adhesives/metabolism , Animals , Caseins/metabolism , Collagen/metabolism , Cross-Linking Reagents , Enzyme Activation , Escherichia coli/enzymology , Escherichia coli/genetics , Gelatin/metabolism , Glutamine/metabolism , Hydrogen-Ion Concentration , Lysine/metabolism , Peptides/metabolism , Plasmids/genetics , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , Transglutaminases/chemistry
6.
Plant Methods ; 15: 1, 2019.
Article in English | MEDLINE | ID: mdl-30622623

ABSTRACT

BACKGROUND: The function of proteins is at large determined by cofactors selectively bound to protein structure. Without chlorophyll specifically bound to protein, light harvesting and photosynthesis would not be possible. The binding of chlorophyll to light harvesting proteins has been extensively studied in reconstitution assays using proteins expressed in vitro; however, the mechanism of the reconstitution reaction remained unclear. We have shown that membrane integral light-harvesting-like protein, LIL3, binds chlorophyll a with a Kd of 146 nM in vitro by thermophoresis. Here, reconstitution of chlorophyll binding to LIL3 has been characterized by four different methods. RESULTS: Structural changes in the reconstitution process have been investigated by light-scattering and differential Trp-fluorescence. For characterization of the chlorophyll binding site at LIL3, the analysis of LIL3 mutants has been conducted using native PAGE and thermophoresis. We find that the oxidized state of dithiothreitol is the essential component for reconstitution of chlorophyll binding to LIL3 in n-Dodecyl ß-d-maltoside micelles at RT. Chlorophyll increased the polydispersity of the micellar states while dithiothreitol maintained LIL3 in a partially unfolded state at RT. Dimerization of LIL3 was abolished if amino acids N174, R176, and E171 were mutated to Ala; while, chlorophyll binding to LIL3 was abolished in mutant N174A, but retained in E171A, and R176A albeit at an about six- and five-fold decreased dissociation constant. Results show that N174 of LIL3 is essential for binding chlorophyll a. CONCLUSIONS: Chlorophyll binding to LIL3 can be shown by thermophoresis, and native gel electrophoresis, while analysis of reconstitution conditions by dynamic light scattering and differential scanning fluorometry are of critical importance for method optimization.

7.
PLoS One ; 13(2): e0192228, 2018.
Article in English | MEDLINE | ID: mdl-29390011

ABSTRACT

The light harvesting like protein 3 (LIL 3) from higher plants, has been linked to functions in chlorophyll and tocopherol biosynthesis, photo-protection and chlorophyll transfer. However, the binding of chlorophyll to LIL3 is unclear. We present a reconstitution protocol for chlorophyll binding to LIL3 in DDM micelles. It is shown in the absence of lipids and carotenoids that reconstitution of chlorophyll binding to in vitro expressed LIL3 requires pre-incubation of reaction partners at room temperature. We show chlorophyll a but not chlorophyll b binding to LIL3 at a molar ratio of 1:1. Neither dynamic light scattering nor native PAGE, enabled a discrimination between binding of chlorophyll a and/or b to LIL3.


Subject(s)
Chlorophyll/metabolism , Light-Harvesting Protein Complexes/metabolism , Micelles , Native Polyacrylamide Gel Electrophoresis , Protein Binding
8.
FEBS Lett ; 589(20 Pt B): 3064-70, 2015 Oct 07.
Article in English | MEDLINE | ID: mdl-26320415

ABSTRACT

The two-helix light harvesting like (Lil) protein Lil3 belongs to the family of chlorophyll binding light harvesting proteins of photosynthetic membranes. A function in tetrapyrrol synthesis and stabilization of geranylgeraniol reductase has been shown. Lil proteins contain the chlorophyll a/b-binding motif; however, binding of chlorophyll has not been demonstrated. We find that Lil3.2 from Arabidopsis thaliana forms heterodimers with Lil3.1 and binds chlorophyll. Lil3.2 heterodimerization (25±7.8 nM) is favored relative to homodimerization (431±59 nM). Interaction of Lil3.2 with chlorophyll a (231±49 nM) suggests that heterodimerization precedes binding of chlorophyll in Arabidopsis thaliana.


Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Chlorophyll/metabolism , Chloroplast Proteins/metabolism , Amino Acid Sequence , Amino Acids/chemistry , Amino Acids/genetics , Amino Acids/metabolism , Arabidopsis/genetics , Arabidopsis Proteins/chemistry , Arabidopsis Proteins/genetics , Binding Sites/genetics , Chloroplast Proteins/chemistry , Chloroplast Proteins/genetics , Electrophoresis, Polyacrylamide Gel , Kinetics , Light-Harvesting Protein Complexes/chemistry , Light-Harvesting Protein Complexes/genetics , Light-Harvesting Protein Complexes/metabolism , Molecular Sequence Data , Protein Binding , Protein Multimerization , Surface Plasmon Resonance
9.
PLoS One ; 10(7): e0133145, 2015.
Article in English | MEDLINE | ID: mdl-26172838

ABSTRACT

The light-harvesting-like (LIL) proteins are a family of membrane proteins that share a chlorophyll a/b-binding motif with the major light-harvesting antenna proteins of oxygenic photoautotrophs. LIL proteins have been associated with the regulation of tetrapyrrol biosynthesis, and plant responses to light-stress. Here, it was found in a native PAGE approach that chlorophyllide, and chlorophyllide plus geranylgeraniolpyrophosphate trigger assembly of Lil3 in three chlorine binding fluorescent protein bands, termed F1, F2, and F3. It is shown that light and chlorophyllide trigger accumulation of protochlorophyllide-oxidoreductase, and chlorophyll synthase in band F3. Chlorophyllide and chlorophyll esterified to geranylgeraniol were identified as basis of fluorescence recorded from band F3. A direct interaction between Lil3, CHS and POR was confirmed in a split ubiquitin assay. In the presence of light or chlorophyllide, geranylgeraniolpyrophosphate was shown to trigger a loss of the F3 band and accumulation of Lil3 and geranylgeranyl reductase in F1 and F2. No direct interaction between Lil3 and geranylgeraniolreductase was identified in a split ubiquitin assay; however, accumulation of chlorophyll esterified to phytol in F1 and F2 corroborated the enzymes assembly. Chlorophyll esterified to phytol and the reaction center protein psbD of photosystem II were identified to accumulate together with psb29, and APX in the fluorescent band F2. Data show that Lil3 assembles with proteins regulating chlorophyll synthesis in etioplasts from barley (Hordeum vulgare L.).


Subject(s)
Chlorophyll/metabolism , Hordeum/metabolism , Light-Harvesting Protein Complexes/metabolism , Chlorophyll A , Chloroplasts/metabolism , Light , Oxidoreductases/metabolism , Photosystem II Protein Complex/metabolism , Phytol/metabolism , Protein Binding/physiology
10.
Methods Mol Biol ; 1295: 415-25, 2015.
Article in English | MEDLINE | ID: mdl-25820737

ABSTRACT

This chapter describes the technology of free flow electrophoresis (FFE) and protocols to separate membrane protein complexes for proteome analysis. FFE is a highly versatile technology applied in the field of protein analysis. It is superior to native PAGE due to its fast continuous processing of sample at high resolution. Additionally, the dynamic separation range from ions, peptides, to proteins, protein complexes, up to organelles, and whole cells makes it the method of choice in the analysis of proteins. FFE is carried out in an aqueous medium without inducing any solid matrix, such as acrylamide, so that it simplifies the analysis of protein complexes for the downstream analysis. Here, we describe the novel zone electrophoresis interval method (IZE-FFE) for separation of protein complexes from the thylakoid membrane of Arabidopsis thaliana by charge only. Protein complexes isolated by IZE FFE were characterized according to molecular weight by Blue Native PAGE and were proteins stained with coomassie.


Subject(s)
Electrophoresis, Polyacrylamide Gel , Membrane Proteins/chemistry , Membrane Proteins/isolation & purification , Arabidopsis Proteins/chemistry , Arabidopsis Proteins/isolation & purification , Electrophoresis, Polyacrylamide Gel/methods , Thylakoids/chemistry , Thylakoids/metabolism
11.
Methods Mol Biol ; 1072: 667-76, 2014.
Article in English | MEDLINE | ID: mdl-24136555

ABSTRACT

Gel electrophoresis has become one of the most important methods for the analysis of proteins and protein complexes in a molecular weight range of 1-10(7) kDa. The separation of membrane protein complexes remained challenging to standardize until the demonstration of Blue Native PAGE in 1991 [1] and Clear Native PAGE in 1994 [2]. We present a robust protocol for high-resolution separation of photosynthetic complexes from Arabidopsis thaliana using lithium dodecyl sulfate as anion in a modified Blue Native PAGE (LDS-PAGE). Here, non-covalently bound chlorophyll is used as a sensitive probe to characterize the assembly/biogenesis of the pigment-protein complexes essential for photosynthesis. The high fluorescence yield recorded from chlorophyll-binding protein complexes can also be used to establish the separation of native protein complexes as an electrophoretic standard.


Subject(s)
Arabidopsis Proteins/isolation & purification , Arabidopsis/metabolism , Electrophoresis, Polyacrylamide Gel/methods , Membrane Proteins/isolation & purification , Sodium Dodecyl Sulfate/chemistry , Solubility , Thylakoids/metabolism
12.
JAMA ; 309(15): 1622-31, 2013 Apr 17.
Article in English | MEDLINE | ID: mdl-23592107

ABSTRACT

IMPORTANCE: The modest effects of clinical studies using intracoronary administration of autologous bone marrow-derived mononuclear cells (BMCs) in patients with chronic postinfarction heart failure may be attributed to impaired homing of BMCs to the target area. Extracorporeal shock wave treatment has been experimentally shown to increase homing factors in the target tissue, resulting in enhanced retention of applied BMCs. OBJECTIVE: To test the hypothesis that targeted cardiac shock wave pretreatment with subsequent application of BMCs improves recovery of left ventricular ejection fraction (LVEF) in patients with chronic heart failure. DESIGN, SETTING, AND PARTICIPANTS: The CELLWAVE double-blind, randomized, placebo-controlled trial conducted among patients with chronic heart failure treated at Goethe University Frankfurt, Germany, between 2006 and 2011. INTERVENTIONS: Single-blind low-dose (n = 42), high-dose (n = 40), or placebo (n = 21) shock wave pretreatment targeted to the left ventricular anterior wall. Twenty-four hours later, patients receiving shock wave pretreatment were randomized to receive double-blind intracoronary infusion of BMCs or placebo, and patients receiving placebo shock wave received intracoronary infusion of BMCs. MAIN OUTCOMES AND MEASURES: Primary end point was change in LVEF from baseline to 4 months in the pooled groups shock wave + placebo infusion vs shock wave + BMCs; secondary end points included regional left ventricular function assessed by magnetic resonance imaging and clinical events. RESULTS: The primary end point was significantly improved in the shock wave + BMCs group (absolute change in LVEF, 3.2% [95% CI, 2.0% to 4.4%]), compared with the shock wave + placebo infusion group (1.0% [95% CI, -0.3% to 2.2%]) (P = .02). Regional wall thickening improved significantly in the shock wave + BMCs group (3.6% [95% CI, 2.0% to 5.2%]) but not in the shock wave + placebo infusion group (0.5% [95% CI, -1.2% to 2.1%]) (P = .01). Overall occurrence of major adverse cardiac events was significantly less frequent in the shock wave + BMCs group (n = 32 events) compared with the placebo shock wave + BMCs (n = 18) and shock wave + placebo infusion (n = 61) groups (hazard ratio, 0.58 [95% CI, 0.40-0.85]; P = .02). CONCLUSIONS AND RELEVANCE: Among patients with postinfarction chronic heart failure, shock wave-facilitated intracoronary administration of BMCs vs shock wave treatment alone resulted in a significant, albeit modest, improvement in LVEF at 4 months. Determining whether the increase in contractile function will translate into improved clinical outcomes requires confirmation in larger clinical end point trials. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00326989.


Subject(s)
Bone Marrow Transplantation/methods , Heart Failure/therapy , High-Energy Shock Waves/therapeutic use , Aged , Combined Modality Therapy , Coronary Angiography , Double-Blind Method , Female , Heart Failure/etiology , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Myocardial Infarction/complications , Single-Blind Method , Stroke Volume , Transplantation, Autologous , Treatment Outcome , Ventricular Dysfunction, Left
13.
Plant Mol Biol ; 81(3): 235-44, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23225155

ABSTRACT

Chloroplasts are descendants of cyanobacteria and divide by binary fission. The number of chloroplasts is regulated in a cell type-specific manner to ensure that specialized cell types can perform their functions optimally. Several protein components of the chloroplast division apparatus have been identified in the past several years, but how this process is regulated in response to developmental status, environmental signals and stress is still unknown. To begin to address this we undertook a proteomic analysis of three accumulation and replication of chloroplasts mutants that show a spectrum of plastid division perturbations. We show that defects in the chloroplast division process results in changes in the abundance of proteins when compared to wild type, but that the profile of the native stromal and membrane complexes remains unchanged. Furthermore, by combining BN-PAGE with protein interaction assays we show that AtFtsZ2-1 and AtFtsZ2-2 assemble together with rpl12A and EF-Tu into a novel chloroplast membrane complex.


Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Chloroplast Proteins/metabolism , Chloroplasts/metabolism , Proteome , Amino Acid Sequence , Arabidopsis/genetics , Arabidopsis/physiology , Chloroplasts/physiology , Chromatography, High Pressure Liquid , Gene Expression Regulation, Plant , Mutation , Peptide Elongation Factor Tu/metabolism , Plant Leaves/genetics , Plant Leaves/metabolism , Plant Leaves/physiology , Plants, Genetically Modified , Proteomics , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Seedlings/genetics , Seedlings/metabolism , Seedlings/physiology , Tandem Mass Spectrometry , Nicotiana/cytology , Nicotiana/genetics , Nicotiana/metabolism , Two-Dimensional Difference Gel Electrophoresis , Two-Hybrid System Techniques
14.
Methods Mol Biol ; 854: 343-53, 2012.
Article in English | MEDLINE | ID: mdl-22311772

ABSTRACT

CyDye labeling and DIGE have not only been proven to work for soluble proteins but also at the level of whole membrane protein complexes. After complex solubilization and CyDye labeling, proteins can be separated by native PAGE which is often combined with SDS PAGE in a subsequent step. By this combination, sizes of complexes as well as their subunit composition can be compared after mixing samples from different physiological states. Plants interact specifically with light via protein-bound pigments. This can be used in combination with CyDye technology to extend the "classical" approach in plant research. As an example, chlorophyll can be excited for fluorescent scanning at the Cy5 excitation wavelength. This property can be used to identify pigment-binding plant complexes and complex subunits isolated from plastid membranes. In this protocol, we present a combination of the conventional CyDye labeling technique with 2D native/SDS PAGE and parallel scanning for CyDyes and fluorescence from endogenous bound chlorophyll for identification of pigment-binding complexes and complex subunits.


Subject(s)
Fluorescent Dyes/chemistry , Plant Proteins/analysis , Plant Proteins/chemistry , Two-Dimensional Difference Gel Electrophoresis/methods , Analytic Sample Preparation Methods , Plant Proteins/isolation & purification
15.
Methods Mol Biol ; 519: 65-82, 2009.
Article in English | MEDLINE | ID: mdl-19381577

ABSTRACT

The proteome of the cell is at the frontier of being too complex for proteomic analysis. Organelles provide a step up. Organelles compartmentalize the cell enabling a proteome, physiology and metabolism analysis in time and in space. Protein complexes separated by electrophoresis have been identified as the next natural level to characterize the organelles' compartmentalized membrane and soluble proteomes by mass spectrometry. Work on mitochondria and chloroplasts has shown where we are in the characterization of complex proteomes to understand the network of endogenous and extrinsic factors which regulate growth and development, adaptation and evolution.


Subject(s)
Organelles/chemistry , Proteome/analysis , Proteomics/methods , Chloroplasts/chemistry , Electrophoresis, Polyacrylamide Gel/instrumentation , Electrophoresis, Polyacrylamide Gel/methods , Mass Spectrometry/instrumentation , Mass Spectrometry/methods , Mitochondria/chemistry , Proteomics/instrumentation
16.
Proteomics ; 9(3): 625-35, 2009 Feb.
Article in English | MEDLINE | ID: mdl-19137553

ABSTRACT

In Photosystem II (PSII), a high number of plastid encoded and membrane integral low molecular weight proteins smaller than 10 kDa, the proteins PsbE, F, H, I, J, K, L, M, N, Tc, Z and the nuclear encoded PsbW, X, Y1, Y2 proteins have been described. Here we show that all low molecular weight proteins of PSII already accumulate in the etioplast membrane fraction in darkness, whereas PsaI and PsaJ of photosystem I (PSI) represent the only low molecular weight proteins that do not accumulate in darkness. We found by BN-PAGE separation of membrane protein complexes and selective MS that the accumulation of one-helix proteins from PSII is light independent and occurs in etioplasts. In contrast, in chloroplasts isolated from light-grown plants, low molecular weight proteins were found to specifically accumulate in PSI and II complexes. Our results demonstrate how plants grown in darkness prepare for the induction of chlorophyll dependent photosystem assembly upon light perception. We anticipate that our investigation will provide the essential means for the analysis of protein assembly in any membrane utilizing low molecular weight protein subunits.


Subject(s)
Chloroplasts/metabolism , Hordeum/metabolism , Membrane Proteins/metabolism , Photosystem II Protein Complex/metabolism , Plant Proteins/metabolism , Molecular Weight , Proteomics/methods , Spectrometry, Mass, Electrospray Ionization
17.
Anal Biochem ; 383(2): 279-88, 2008 Dec 15.
Article in English | MEDLINE | ID: mdl-18804444

ABSTRACT

Photosystem II is a multimeric protein complex of the thylakoid membrane in chloroplasts. Approximately half of the at least 26 different integral membrane protein subunits have molecular masses lower than 10 kDa. After one-dimensional (1D) or two-dimensional (2D) polyacrylamide gel electrophoresis (PAGE) separation, followed by enzymatic digestion of detected proteins, hardly any of these low-molecular-weight (LMW) subunits are detectable. Therefore, we developed a method for the analysis of highly hydrophobic LMW proteins. Intact proteins are extracted from acrylamide gels using a mixture of formic acid and organic solvent, precipitated with acetone, and analyzed by "top-down" mass spectrometry (MS). After offline nanoESI (electrospray ionization) MS, all LMW one-helix proteins from photosystem II were detected. In the four detected photosystem II supercomplexes of Nicotiana tabacum wild-type plants, 11 different one-helix proteins were identified as PsbE, -F, -H, -I, -K, -L, -M, -Tc, -W, and two isoforms of PsbX. The proteins PsbJ, -Y1, and -Y2 were localized in the buffer front after blue native (BN) PAGE, indicating their release during solubilization. Assembled PsbW is detected exclusively in supercomplexes, whereas it is absent in photosystem II core complexes, corroborating the protein's function for assembly of the light-harvesting complexes. This approach will substantiate gel-blot immunoanalysis for localization and identification of LMW protein subunits in any membrane protein complex.


Subject(s)
Membrane Proteins/chemistry , Nicotiana/enzymology , Photosystem II Protein Complex/chemistry , Amino Acid Sequence , Dimerization , Electrophoresis, Polyacrylamide Gel , Molecular Sequence Data , Molecular Weight , Nanotechnology , Organic Chemicals/chemistry , Oxidation-Reduction , Protein Structure, Quaternary , Protein Structure, Secondary , Sequence Homology, Amino Acid , Solvents/chemistry , Spectrometry, Mass, Electrospray Ionization , Tandem Mass Spectrometry , Thylakoids/chemistry , Nicotiana/cytology
18.
J Proteomics ; 71(3): 277-83, 2008 Aug 21.
Article in English | MEDLINE | ID: mdl-18573355

ABSTRACT

Blue native PAGE is an electrophoretic technique for high-resolution separation of membrane proteins. The method has been proven especially useful for investigation of native protein complexes enabling a characterization of potential protein-protein interactions in the context of functional proteomics. Blue native PAGE is easy to realise, results are reproducible and a high number of protocols are available. However, care should be taken during solubilization of protein complexes to achieve significant results in BN-PAGE analysis. Solubilization of membranes and proteins is not only influenced by detergent-lipid and detergent-protein interactions but also by lipid-lipid, lipid-protein and protein-protein interactions. Interactions have been investigated experimentally and theoretically. But, in practice, the experimental results do not always mirror the theoretical basis and therefore optimal solubilization conditions for each membrane and membrane protein complex should be investigated individually to tap the full potential of BN-PAGE analysis.


Subject(s)
Electrophoresis, Polyacrylamide Gel/methods , Proteomics/methods , Animals , Detergents/chemistry , Detergents/pharmacology , Fungal Proteins/chemistry , Ions , Isoelectric Focusing/methods , Lipids/chemistry , Membrane Proteins/chemistry , Mitochondria/metabolism , Mitochondrial Proteins/metabolism , Protein Interaction Mapping , Proteome
19.
Proteomics ; 7 Suppl 1: 6-16, 2007 Sep.
Article in English | MEDLINE | ID: mdl-17893852

ABSTRACT

Natural compartmentalization makes proteome analysis of the cell, cell organelles and organelle subfractions possible. Protein complexes are the basis for the next level of compartmentalization that can be addressed well with proteomic technology. Protein complexes organize and maintain the cellular and organelle functions on all levels of complexity in time and space. Cell development and division, transcription and translation, respiration and photosynthesis, transport and metabolism can be defined by the activity of protein complexes. Since a large part of the protein complexes of the cell body are inserted in lipid membrane phases, isolation, separation and protein subunit identification were difficult to address. Blue native polyacrylamide gel electrophoresis (BN-PAGE) provides us with the technology for high resolution separation of membrane protein complexes. Here, we show that high resolution separation of protein complexes by BN-PAGE requires the establishment of a detailed solubilisation strategy. We show that BN/SDS-PAGE provides the scientist with a high resolution array of protein subunits which allows analysis of the specific subunit stoichiometry of a protein complex as well as the assembly of protein complexes by standard protein detection methodology like DIGE, gelblot analysis and mass spectrometry. We envision BN-PAGE to precede classical 2D IEF/SDS-analysis for detailed characterization of membrane proteomes.


Subject(s)
Electrophoresis, Gel, Two-Dimensional/methods , Electrophoresis, Polyacrylamide Gel/methods , Membrane Proteins/isolation & purification , Multiprotein Complexes/analysis , Cell Compartmentation , Digitonin/pharmacology , Glucosides/pharmacology , Isoelectric Focusing , Mass Spectrometry , Micelles , Rosaniline Dyes , Solubility , Thylakoids/chemistry
20.
Anal Bioanal Chem ; 389(4): 991-1002, 2007 Oct.
Article in English | MEDLINE | ID: mdl-17639354

ABSTRACT

The proteomic characterization of proteins and protein complexes from cells and cell organelles is the next challenge for investigation of the cell. After isolation of the cell compartment, three steps have to be performed in the laboratory to yield information about the proteins present. The protein mixtures must be separated into single species, broken down into peptides, and, finally, identified by mass spectrometry. Most scientists engaged in proteomics separate proteins by electrophoresis. For characterization and identification of proteomes, mass spectrometry of peptides is the method of choice. To combine electrophoresis and mass spectrometry, sample preparation by "in-gel digestion" has been developed. Many procedures are available for in-gel digestion, which inspired us to review in-gel digestion approaches.


Subject(s)
Electrophoresis, Polyacrylamide Gel/methods , Mass Spectrometry/methods , Proteome/analysis , Proteomics/methods , Alkylation , Oxidation-Reduction , Peptide Fragments/analysis , Peptide Fragments/chemistry , Peptide Fragments/isolation & purification , Peptide Hydrolases/chemistry , Proteins/analysis , Proteins/chemistry , Proteins/isolation & purification , Proteome/chemistry , Staining and Labeling/methods
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