Utilising BC observations to estimate CO contributions from fossil fuel and biomass burning in the Central Himalayan region.

The Himalayan region is adversely affected by the increasing anthropogenic emissions from the adjacent Indo-Gangetic plain. However, source apportionment studies for the Himalayan region that are crucial for estimating CO concentration, are grossly insufficient, to say the least. It is in this context that our study reported here assumes significance. This study utilizes five years (2014-2018) of ground-based observations of eBC and multiple linear regression framework (MLR) to estimate CO and segregate its fossil fuel and biomass emission fractions at a high-altitude (1958 m) site in the Central Himalayas. The results show that MERRA2 always underestimates the observed CO; MOPITT has a high monthly difference ranging from -32% to +57% while WRF-Chem simulations underestimate CO from February to June and overestimate in other months. In contrast, CO estimated from MLR replicates diurnal and monthly variations and estimates CO with an r2 > 0.8 for 2014-2017. The CO predicted during 2018 closely follows the observed variations, and its mixing ratios lie within ±17% of the observed CO. The results reveal a unimodal diurnal variation of CO, COff (ff: fossil fuel) and CObb (bb: biomass burning) governed by the boundary layer evolution and upslope winds. COff has a higher diurnal amplitude (39.1-67.8 ppb) than CObb (5.7-33.5 ppb). Overall, COff is the major contributor (27%) in CO after its background fraction (58%). CObb fraction reaches a maximum (28%) during spring, a period of increased agricultural and forest fires in Northern India. In comparison, WRF-Chem tracer runs underestimate CObb (-38% to -98%) while they overestimate the anthropogenic CO during monsoon. This study thus attempts to address the lack of continuous CO monitoring and the need to segregate its fossil fuel and biomass sources, specifically over the Central Himalayas, by employing a methodology that utilizes the existing network of eBC observations.

Operationalising the "One Health" approach in India: facilitators of and barriers to effective cross-sector convergence for zoonoses prevention and control.

BACKGROUND: There is a strong policy impetus for the One Health cross-sectoral approach to address the complex challenge of zoonotic diseases, particularly in low/lower middle income countries (LMICs). Yet the implementation of this approach in LMIC contexts such as India has proven challenging, due partly to the relatively limited practical guidance and understanding on how to foster and sustain cross-sector collaborations. This study addresses this gap by exploring the facilitators of and barriers to successful convergence between the human, animal and environmental health sectors in India. METHODS: A mixed methods study was conducted using a detailed content review of national policy documents and in-depth semi-structured interview data on zoonotic disease management in India. In total, 29 policy documents were reviewed and 15 key informant interviews were undertaken with national and state level policymakers, disease managers and experts operating within the human-animal-environment interface of zoonotic disease control. RESULTS: Our findings suggest that there is limited policy visibility of zoonotic diseases, although global zoonoses, especially those identified to be of pandemic potential by international organisations (e.g. CDC, WHO and OIE) rather than local, high burden endemic diseases, have high recognition in the existing policy agenda setting. Despite the widespread acknowledgement of the importance of cross-sectoral collaboration, a myriad of factors operated to either constrain or facilitate the success of cross-sectoral convergence at different stages (i.e. information-sharing, undertaking common activities and merging resources and infrastructure) of cross-sectoral action. Importantly, participants identified the lack of supportive policies, conflicting departmental priorities and limited institutional capacities as major barriers that hamper effective cross-sectoral collaboration on zoonotic disease control. Building on existing informal inter-personal relationships and collaboration platforms were suggested by participants as the way forward. CONCLUSION: Our findings point to the importance of strengthening existing national policy frameworks as a first step for leveraging cross-sectoral capacity for improved disease surveillance and interventions. This requires the contextual adaptation of the One Health approach in a manner that is sensitive to the underlying socio-political, institutional and cultural context that determines and shapes outcomes of cross-sector collaborative arrangements.

Cosmic microwave background trispectrum and primordial magnetic field limits.

Primordial magnetic fields will generate non-gaussian signals in the cosmic microwave background (CMB) as magnetic stresses and the temperature anisotropy they induce depend quadratically on the magnetic field. We compute a new measure of magnetic non-gaussianity, the CMB trispectrum, on large angular scales, sourced via the Sachs-Wolfe effect. The trispectra induced by magnetic energy density and by magnetic scalar anisotropic stress are found to have typical magnitudes of approximately a few times 10(-29) and 10(-19), respectively. Observational limits on CMB non-gaussianity from WMAP data allow us to conservatively set upper limits of a nG, and plausibly sub-nG, on the present value of the primordial cosmic magnetic field. This represents the tightest limit so far on the strength of primordial magnetic fields, on Mpc scales, and is better than limits from the CMB bispectrum and all modes in the CMB power spectrum. Thus, the CMB trispectrum is a new and more sensitive probe of primordial magnetic fields on large scales.

High-dose chemotherapy and auto-SCT in elderly patients with Hodgkin's lymphoma.

Our purpose was to assess efficacy and toxicity of high-dose chemotherapy (HDCT) and ASCT in patients with relapsed and refractory Hodgkin's lymphoma (HL) aged 60 years and older and compare the results with a group of younger HL patients treated in a similar manner. We identified 15 consecutive patients, with HL aged 60 years and older who underwent HDCT (etoposide 60 mg/kg+ melphalan 160 mg/m(2)) and ASCT at our institution from May 2001 to March 2008. The results were compared with a cohort of 157 younger HL patients treated in a similar manner from January 1999 to December 2006. After a median follow-up of 2.5 years, PFS at 3 years after ASCT was 73% (95% confidence interval (CI) 37-90) for the older group and 56% (95% CI 46-64) for the younger group (P=0.45); OS after ASCT was 88% (95% CI 39-98) for the older group and 84% (95% CI 75-90) for the younger group (P=0.80). No transplant-related deaths were seen. Our study suggests that ASCT is feasible for selected elderly patients with HL, giving similar results to younger patients in terms of survival and toxicity.

Cosmic microwave background bispectrum from primordial magnetic fields on large angular scales.

Primordial magnetic fields lead to non-Gaussian signals in the cosmic microwave background (CMB) even at the lowest order, as magnetic stresses and the temperature anisotropy they induce depend quadratically on the magnetic field. In contrast, CMB non-Gaussianity due to inflationary scalar perturbations arises only as a higher-order effect. We propose a novel probe of stochastic primordial magnetic fields that exploits the characteristic CMB non-Gaussianity that they induce. We compute the CMB bispectrum (b(l1l2l3)) induced by such fields on large angular scales. We find a typical value of l1(l1 + 1)l3(l3 + 1)b(l1l2l3) approximately 10(-22), for magnetic fields of strength B0 approximately 3 nG and with a nearly scale invariant magnetic spectrum. Observational limits on the bispectrum allow us to set upper limits on B0 approximately 35 nG.

Hazardous alcohol use in rural southern India: nature, prevalence and risk factors.

BACKGROUND: There is a dearth of data on the hazardous use of alcohol in rural India. METHODS: We examined the nature, prevalence and factors associated with hazardous use of alcohol among men in a rural community in southern India. We used stratified sampling to select subjects from the Kaniyambadi block and employed 'AUDIT', a standard instrument, to assess the use of alcohol. RESULTS: The prevalence of life-time use, use in the past year and hazardous use of alcohol was 46.7%, 34.8% and 14.2%, respectively. Using Indian made foreign liquor (OR 20.51; 95% CI 8.81-47.75) and living in a village which brewed illicit alcohol (OR 2.82; 95% CI 1.39-5.72) were risk factors for hazardous use while education (OR 0.39; 95% CI 0.21-0.72) was protective. These factors remained significantly associated with hazardous use after adjusting for age and education using logistic regression. CONCLUSION: The relationship between the availability of illicit and commercial alcohol and its hazardous use suggests the need for an alcohol policy which takes into account health and economic issues and also implements the law to prevent the negative impact of problem drinking.

Utility of subsequent conventional dose chemotherapy in relapsed/refractory transplant-eligible patients with diffuse large B-cell lymphoma failing platinum-based salvage chemotherapy.

Up to 60% of patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL) do not respond to second-line (salvage) chemotherapy and hence are not offered autologous hematopoietic cell transplantation (AHCT). The utility of further salvage chemotherapy in an attempt to proceed with AHCT remains undefined. The authors reviewed 201 patients with DLBCL relapsed/refractory to anthracycline-based chemotherapy who received first-line salvage chemotherapy containing cis-platinum. Of the 120 non-responders to first-line platinum-based salvage chemotherapy, 73 received second-line salvage chemotherapy. The response rate to second-line salvage chemotherapy was 14%. Factors predicting lack of response were progression on primary therapy (p = 0.007), abnormal lactate dehydrogenase findings (p = 0.0027) and tumor bulk (p = 0.013) at second progression. Eight patients who responded received AHCT and appeared to have comparable survival to those transplanted after one salvage regimen. The authors conclude that the utility of second-line salvage chemotherapy is low, and that it is best reserved for patients demonstrating initial anthracycline sensitivity and low tumor burden.

G-CSF-stimulated BM progenitor cells supplement suboptimal peripheral blood hematopoietic progenitor cell collections for auto transplantation.

Peripheral blood hematopoietic progenitor cells (PBHC) are the standard source of support for high-dose chemotherapy because of faster recovery of marrow function. Unfortunately, a proportion of patients are unable to mobilize adequate progenitors to proceed to autologous hematopoietic cell transplant (AHCT). Granulocyte-CSF-stimulated BM-derived hematopoietic progenitor cells (BMHC) may circumvent this problem. From 1999 to 2006, 52 patients (cases) with AML, Hodgkin (HL) or non-Hodgkin's lymphoma (NHL) in whom PBHC mobilization failed underwent a G-CSF-stimulated bone marrow harvest and proceeded to AHCT. Their outcome was compared with 422 patients (controls) with AML, HL and NHL undergoing AHCT using only PBHC. Twenty-three patients received BMHC alone and 29 patients received a combination of PBHC and BMHC. Median engraftment time for neutrophils (>0.5 x 10(9)/l) and platelets (>20 x 10(9)/l) were 14 and 27 days, but significantly longer when compared with controls (11 days, 11 days, P<0.0001). Patients receiving both PBHC and BMHC had faster engraftment, when compared with those receiving BMHC alone (P<0.001). In conclusion, performing an AHCT using G-CSF-stimulated BMHC in patients failing PBHC collection is feasible with faster engraftment seen in patients receiving both BMHC and PBHC over BMHC alone.

The relationship between absolute lymphocyte count with PFS in patients with Hodgkin's lymphoma undergoing autologous hematopoietic cell transplant.

Previous reports in Hodgkin's lymphoma (HL) patients undergoing autologous hematopoietic cell transplantation (AHCT) have demonstrated a significant association between the absolute lymphocyte count at day 15 (ALC-15) with survival. To evaluate this finding further, we analyzed 146 patients with relapsed/refractory HL who underwent AHCT to evaluate the relationship between lymphocyte counts at apheresis and at two time points (days 15 and 90) after AHCT with PFS. We found no association between the ALC-15 and the ALC-90 with PFS. We found lymphocyte counts at apheresis and disease sensitive to salvage chemotherapy were predictive of PFS. In conclusion, our study does provide some support for the theory that the immune system may be important in disease control but further and more detailed studies in this area are required.

Ins and outs of inferior vena cava filters in patients with venous thromboembolism: the experience at Monash Medical Centre and review of the published reports.

BACKGROUND: Inferior vena cava (IVC) filters are an alternative management strategy to anticoagulation in patients with venous thromboembolism (VTE). However, an IVC filter has its own inherent risks and complications and may not be the best management strategy. The aims of this study were to evaluate our institution's practice of permanent Vena Tech (B. Braun Medical S.A., Boulogne, France) and retrievable Gunther Tulip (William Cook Europe, Bjaeverskov) IVC filters and to review the available published reports. METHODS: Retrospective single centre audit from the medical record. RESULTS: Eighty-three and 42 patients had a VT and GT filter inserted, respectively. Median age was 57 years for VT and 63 years for GT. The majority (75% for VT and 83% for GT) was inserted for acute VTE and contraindication to anticoagulation. Both filters were efficacious at preventing pulmonary embolism (PE) and there was a low rate of recurrent deep venous thrombosis in both groups. Insertion-related complications were low in both groups. Of the GT filters (n = 42), 16 were deemed an ongoing requirement, and thus, removal was not planned. In a further six patients, there was insufficient documentation as to why removal was not planned. Removal was attempted in 19 patients and was successful in 11. Failure of removal was as a result of clot in the filter (n = 7) or inability to snare it (n = 1). CONCLUSIONS: Both the permanent and retrievable filters are efficacious at preventing PE and are associated with a low complication rate. Planned removal of the GT filter may not be possible in a significant proportion of cases.

Lack of evidence of disease contamination in ovarian tissue harvested for cryopreservation from patients with Hodgkin lymphoma and analysis of factors predictive of oocyte yield.

Ovarian cryopreservation is a promising technique to preserve fertility in women with Hodgkin lymphoma (HL) treated with chemotherapy. Thus, the aim of this study was to examine harvested ovarian tissue for subclinical involvement by HL by morphology/immunohistochemistry, and to define patient and treatment factors predictive of oocyte yield. This was a retrospective analysis of 26 ovarian tissue samples harvested for cryopreservation from women with HL. Histology, immunohistochemistry and follicle density (number mm(-3)) was examined. Disease status and preharvest chemotherapy details were obtained on 24 patients. The median age was 22 years (range 13-29). Seven of 24 patients had infradiaphragmatic disease at time of harvest. Nine of 20 patients had received chemotherapy preharvest (ABVD (Adriamycin), Bleomycin, Vinblastine and Dacarbazine) = 7, other regimens = 2). The seven receiving ABVD showed no difference in follicle density compared to patients not receiving treatment (n = 14); (median = 1555 vs 1620 mm3 P = 0.97). Follicle density measurement showed no correlation with patient age (R2 = 0.0001, P = 0.99). There was no evidence of HL involvement in the 26 samples examined (95% CI = 0-11%). In conclusion, subclinical involvement of HL has not been identified in ovarian tissue, even when patients have infradiaphragmatic disease. Furthermore, the quality of tissue harvested does not appear to be adversely affected by patient's age or prior ABVD chemotherapy.

The effect of the Hyper-CVAD chemotherapy regimen on fertility and ovarian function.

Hyper-CVAD is a dose intensive chemotherapy regimen that has been used successfully in lymphoblastic lymphoma and leukaemia. However, the effect on ovarian function has not been evaluated. Thus, we undertook a retrospective analysis of patients under 40 years of age who had Hyper-CVAD as initial therapy and documented ovarian function as defined by regular menstruation off hormonal agents or naturally conceiving. Of the 12 patients identified, 7 were evaluable. Median age was 25. Six patients had resumption of regular menstruation and three of these women have conceived naturally. In conclusion, resumption of normal fertility is probable post-treatment with Hyper-CVAD.

Cosmic microwave background polarization signals from tangled magnetic fields.

Tangled, primordial cosmic magnetic fields create small rotational velocity perturbations on the last scattering surface of the cosmic microwave background radiation. For fields which redshift to a present value of B0 = 3 x 10(-9) G, these vector modes are shown to generate polarization anisotropies of order 0.1-4 microK on small angular scales (500

Ethyl 2-[N-(tert-butyloxycarbonyl)-L-alanylamino]-4-methyl-1, 3-thiazole-5-carboxylate reveals a trans orientation of the preceding amide N--H with respect to the thiazole-ring sulfur.

The title molecule, C(15)H(23)N(3)O(5)S, was prepared as a synthetic precursor to 4-methylthiazole-based DNA minor groove binders which would bear chiral amino acids in the sequence. The crystallographic evidence presented herein shows that the aromatic amide NH group preceding the thiazole ring points away from the direction of sulfur. The molecule is biplanar, with the dihedral angle between the N-terminus peptide moiety and the thiazole-containing plane being 49.7 (5) degrees, with a bend at the Calpha carbon.

Biochemical and functional analysis of mice deficient in expression of the CD45-associated phosphoprotein LPAP.

The role of the CD45-associated phosphoprotein (LPAP / CD45-AP) during an immune response remains unclear. To understand better the function of LPAP we generated LPAP-deficient mice by disrupting exon 2 of the LPAP gene. LPAP-null mice were healthy and did not show gross abnormalities compared to their wild-type littermates. However, immunofluorescence analysis of T and B lymphocytes revealed a reduced expression of CD45, which did not affect a particular subpopulation. In contrast to a recent report (Matsuda et al., J. Exp. Med. 1998. 187: 1863 - 1870) we neither observed significant alterations of the assembly of the CD45 / lck-complex nor of polyclonal T-cell responses. However, lymphnodes from LPAP-null mice showed increased cellularity, which could indicate that expression of LPAP might be required to prevent expansion of lymphocytes in particular lymphatic organs rather than potentiating immune responses.

Preference for syn conformation: crystal structures of free acid and ammonium salt of adenosine 2'-monophosphate: an inhibitor of RNase T1.

This paper reports the crystal structures of free acid and ammonium salt of adenosine 2'-monophosphate (2'-AMP). 2'-AMP crystallizes in the hexagonal space group P6(5)22 with a = 9.530(3) A, c = 73.422(2) A, and Z= 12. 2'-AMP.NH4 crystallizes in the trigonal space group P3(1) with a = 9.003(2) A, c = 34.743(2) A and Z= 6. Both the structures were solved by direct methods and refined by full matrix least- squares method to final R factors of 0.080 and 0.038 for 2'-AMP and 2'-AMP.NH4 respectively. The adenine bases of both the structures are in syn conformation contrasting with the anti geometry in 3'-AMP, 5'-AMP and the enzyme bound state. Ribose moiety of 2'-AMP is in C2' -endo conformation. However, the ribose moieties of both the nucleotide molecules display C2'-endo-C3'-exo twist conformation in 2'- AMP.NH4 structure. Both structures demonstrate g+ conformation about C4' -C5' bond. 2'-AMP and one of the nucleotide molecules of 2'-AMP.NH4 are protonated at N1 and the ammonium ion is involved in a bifurcated hydrogen bond with O3' B and O3A atoms. A characteristic feature of both the structures is the intramolecular O5' -N3 hydrogen bond. Our crystallographic results on 2'-AMP corroborates the earlier conclusion that the enzyme-bound state is not the lowest energy state of this nucleotide. 2' -AMP displays base-ribose 04' stacking not seen in the 2'-AMP.NH4 structure. Theoretical and experimental studies on 2'-, 3'- and 5'-AMP structures have been discussed.

Metal-nucleotide interactions: crystal structures of alkali (Li+, Na+, K+) and alkaline earth (Ca2+, Mg2+) metal complexes of adenosine 2'-monophosphate.

Crystal structures of lithium, sodium, potassium, calcium and magnesium salts of adenosine 2'-monophosphate (2'-AMP) have been obtained at atomic resolution by X-ray crystallographic methods. 2'-AMP.Li belongs to the monoclinic space group P2(1) with a = 7.472(3)A, b = 26.853(6) A, c = 9.184(1)A, b = 113.36(1)A and Z= 4. 2'-AMP.Na and 2'-AMP.K crystallize in the trigonal space groups P3(1) and P3(1)21 with a = 8.762(1)A, c = 34.630(5)A, Z= 6 and a = 8.931(4), Ac = 34.852(9)A and Z= 6 respectively while 2'-AMP.Ca and 2'-AMP.Mg belong to space groups P6(5)22 and P2(1) with cell parameters a = 9.487(2), c = 74.622(13), Z = 12 and a = 4.973(1), b = 10.023(2), c = 16.506(2), beta = 91.1(0) and Z = 2 respectively. All the structures were solved by direct methods and refined by full matrix least-squares to final R factors of 0.033, 0.028, 0.075, 0.069 and 0.030 for 2'-AMP.Li, 2'-AMP.Na, 2'- AMP.K, 2'-AMP.Ca and 2'-AMP.Mg, respectively. The neutral adenine bases in all the structures are in syn conformation stabilized by the O5'-N3 intramolecular hydrogen bond as in free acid and ammonium complex reported earlier. In striking contrast, the adenine base is in the anti geometry (chiCN = -156.4(2)degrees) in 2'-AMP.Mg. Ribose moieties adopt C2'-endo puckering in 2'-AMP.Li and 2'-AMP.Ca, C2'-endo-C3'-exo twist puckering in 2'-AMP.Na and 2'-AMP.K and a C3'-endo-C2'-exo twist puckering in 2'-AMP.Mg structure. The conformation about the exocyclic C4'-C5' bond is the commonly observed gauche-gauche (g+) in all the structures except the gauche- trans (g-) conformation observed in 2'-AMP.Mg structure. Lithium ions coordinate with water, ribose and phosphate oxygens at distances 1.88 to 1.99A. Na+ ions and K+ ions interact with phosphate and ribose oxygens directly and with N7 indirectly through a water oxygen. A distinct feature of 2'-AMP.Na and 2'-AMP.K structures is the involvement of ribose 04' in metal coordination. The calcium ion situated on a two-fold axis coordinates directly with three oxygens OW1, OW2 and O2 and their symmetry mates at distances 2.18 to 2.42A forming an octahedron. A classic example of an exception to the existence of the O5'-N3 intramolecular hydorgen bond is the 2'-AMP.Mg strucure. Magnesium ion forms an octahedral coordination with three water and three phosphate oxygens at distances ranging from 2.02 to 2.11 A. A noteworthy feature of its coordination is the indirect link with N3 through OW3 oxygen resulting in macrochelation between the base and the phosphate group. Greater affnity of metal clays towards 5' compared to 2' and 3' nucleotides (J. Lawless, E. Edelson, and L. Manning, Am. Chem. Soc. Northwest Region Meeting, Seattle. 1978) due to macrochelation infered from solution studies (S. S. Massoud, H. Sigel, Eur J. Biochem. 179, 451-458 (1989)) and interligand hydrogen bonding induced by metals postulated from metal-nucleotide structures in solid state (V. Swaminathan and M. Sundaralingam, CRC. Crit. Rev. Biochem. 6, 245-336 (1979)) are borne out by our structures also. The stacking patterns of adenine bases of both 2'-AMP.Na and 2'-AMP.K structures resemble the 2'-AMP.NH4 structure reported in the previous article. 2'-AMP.Li, 2'-AMP.Ca and 2'-AMP.Mg structures display base-ribose 04' stacking. An overview of interaction of monovalent and divalent cations with 2' and 5'-nucleotides has been presented.

Characterization of mice deficient in interleukin-1 beta converting enzyme.

Interleukin-1 beta converting enzyme (ICE) processes the inactive prolL-1 beta to the proinflammatory mature IL-1 beta. ICE belongs to a family of cysteine proteases that have been implicated in apoptosis. To address the biological functions of ICE, we generated ICE-deficient mice through gene targeting technology. ICE-deficient mice developed normally, appeared healthy, and were fertile. Peritoneal macrophages from ICE-deficient mice underwent apoptosis normally upon ATP treatment. Thymocytes from young ICE-deficient mice also underwent apoptosis when triggered by dexamethasone, gamma irradiation, or aging. ICE-deficient mice had a major defect in the production of mature IL-1 beta and had impaired IL-1 alpha production on LPS stimulation in vitro and in vivo. ICE-deficient mice were resistant to LPS-induced endotoxic shock.

Activation of an interleukin 1 converting enzyme-dependent apoptosis pathway by granzyme B.

Cytotoxic T lymphocytes (CTL) can induce apoptosis through a granzyme B-based killing mechanism. Here we show that in cells undergoing apoptosis by granzyme B, both p45 pro-interleukin 1 beta converting enzyme (ICE) and pro-CPP32 are processed. Using ICE deficient (ICE -/-) mice, embryonic fibroblasts exhibit high levels of resistance to apoptosis by granzyme B or granzyme 3, while B lymphoblasts are granzyme B-resistant, thus identifying an ICE-dependent apoptotic pathway that is activated by CTL granzymes. In contrast, an alternative ICE-independent pathway must also be activated as ICE -/- thymocytes remain susceptible to apoptosis by both granzymes. In ICE -/- B cells or HeLa cells transfected with mutant inactive ICE or Ich-1S that exhibit resistance to granzyme B, CPP32 is processed to p17 and poly(ADP-ribose) polymerase is cleaved indicating that this protease although activated was not associated with an apoptotic nuclear phenotype. Using the peptide inhibitor Ac-DEVD-CHO, apoptosis as well as p45 ICE hydrolysis are suppressed in HeLa cells, suggesting that a CPP32-like protease is upstream of ICE. In contrast, p34cdc2 kinase, which is required for granzyme B-induced apoptosis, remains inactive in ICE -/- B cells indicating it is downstream of ICE. We conclude that granzyme B activates an ICE-dependent cell death pathway in some cell types and requires a CPP32-like Ac-DEVD-CHO inhibitable protease acting upstream to initiate apoptosis.

Differences in the metal ion structure between Sr- and Ca-prothrombin fragment 1.

The structure of Sr-prothrombin fragment 1 has been solved and refined by restrained least-squares methods at 2.5-A resolution to a crystallographic R value of 0.167. The protein structure is very similar to that of Ca-fragment 1. A polymeric array of five Sr2+ ions separated by about 4.0 A is buried among six gamma-carboxyglutamic acid (Gla) residues; three other Sr2+ ions interact with other Gla residues and are located further apart. One of these was not found in the Ca-fragment 1 structure. The coordination of the Sr2+ ions resembles that of Ca2+, but there are some significant differences between them. The most notable is the lack of water coordination with Sr2+ ions and two conformations for Gla 8, which change the coordination of Sr-2 and Sr-3. A hexose moiety of an oligosaccharide was located in the vicinity of Asn101 that was flexibly disordered in Ca-fragment 1. The new Sr2+ ion found may be involved in metal ion phospholipid binding interactions along with Sr-1, and Sr-7, Sr-8.