|3jtc, resolution 1.60Å ()|
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Importance of Mg2+ in the Ca2+-Dependent Folding of the gamma-Carboxyglutamic Acid Domains of Vitamin K-Dependent clotting and anticlotting Proteins
Crystal structures of factor (F) VIIa/soluble tissue factor (TF), obtained under high Mg2+ (50mM Mg2+/5mM Ca2+), have three of seven Ca2+ sites in the gamma-carboxyglutamic acid (Gla) domain replaced by Mg2+ at positions 1, 4, and 7. We now report structures under low Mg2+ (2.5mM Mg2+/5mM Ca2+) as well as under high Ca2+ (5mM Mg2+/45mM Ca2+). Under low Mg2+, four Ca2+ and three Mg2+ occupy the same positions as in high-Mg2+ structures. Conversely, under low Mg2+, reexamination of the structure of Gla domain of activated Protein C (APC) complexed with soluble endothelial Protein C receptor (sEPCR) has position 4 occupied by Ca2+ and positions 1 and 7 by Mg2+. Nonetheless, in direct binding experiments, Mg2+ replaced three Ca2+ sites in the unliganded Protein C or APC. Further, the high-Ca2+ condition was necessary to replace Mg4 in the FVIIa/soluble TF structure. In biological studies, Mg2+ enhanced phospholipid binding to FVIIa and APC at physiological Ca2+. Additionally, Mg2+ potentiated phospholipid-dependent activations of FIX and FX by FVIIa/TF and inactivation of activated factor V by APC. Since APC and FVIIa bind to sEPCR involving similar interactions, we conclude that under the low-Mg2+ condition, sEPCR binding to APC-Gla (or FVIIa-Gla) replaces Mg4 by Ca4 with an attendant conformational change in the Gla domain omega-loop. Moreover, since phospholipid and sEPCR bind to FVIIa or APC via the omega-loop, we predict that phospholipid binding also induces the functional Ca4 conformation in this loop. Cumulatively, the data illustrate that Mg2+ and Ca2+ act in concert to promote coagulation and anticoagulation.
Structural and Functional Studies of gamma-Carboxyglutamic Acid Domains of Factor VIIa and Activated Protein C: Role of Magnesium at Physiological Calcium., Vadivel K, Agah S, Messer AS, Cascio D, Bajaj MS, Krishnaswamy S, Esmon CT, Padmanabhan K, Bajaj SP, J Mol Biol. 2013 Feb 20. pii: S0022-2836(13)00104-6. doi:, 10.1016/j.jmb.2013.02.017. PMID:23454357
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
[PROC_HUMAN] Defects in PROC are the cause of thrombophilia due to protein C deficiency, autosomal dominant (THPH3) [MIM:176860]. A hemostatic disorder characterized by impaired regulation of blood coagulation and a tendency to recurrent venous thrombosis. However, many adults with heterozygous disease may be asymptomatic. Individuals with decreased amounts of protein C are classically referred to as having type I protein C deficiency and those with normal amounts of a functionally defective protein as having type II deficiency.              Defects in PROC are the cause of thrombophilia due to protein C deficiency, autosomal recessive (THPH4) [MIM:612304]. A hemostatic disorder characterized by impaired regulation of blood coagulation and a tendency to recurrent venous thrombosis. It results in a thrombotic condition that can manifest as a severe neonatal disorder or as a milder disorder with late-onset thrombophilia. The severe form leads to neonatal death through massive neonatal venous thrombosis. Often associated with ecchymotic skin lesions which can turn necrotic called purpura fulminans, this disorder is very rare.
[EPCR_HUMAN] Binds activated protein C. Enhances protein C activation by the thrombin-thrombomodulin complex; plays a role in the protein C pathway controlling blood coagulation. [PROC_HUMAN] Protein C is a vitamin K-dependent serine protease that regulates blood coagulation by inactivating factors Va and VIIIa in the presence of calcium ions and phospholipids.
About this Structure
- Vadivel K, Agah S, Messer AS, Cascio D, Bajaj MS, Krishnaswamy S, Esmon CT, Padmanabhan K, Bajaj SP. Structural and Functional Studies of gamma-Carboxyglutamic Acid Domains of Factor VIIa and Activated Protein C: Role of Magnesium at Physiological Calcium. J Mol Biol. 2013 Feb 20. pii: S0022-2836(13)00104-6. doi:, 10.1016/j.jmb.2013.02.017. PMID:23454357 doi:10.1016/j.jmb.2013.02.017
- ↑ Miyata T, Zheng YZ, Sakata T, Kato H. Protein C Osaka 10 with aberrant propeptide processing: loss of anticoagulant activity due to an amino acid substitution in the protein C precursor. Thromb Haemost. 1995 Oct;74(4):1003-8. PMID:8560401
- ↑ Romeo G, Hassan HJ, Staempfli S, Roncuzzi L, Cianetti L, Leonardi A, Vicente V, Mannucci PM, Bertina R, Peschle C, et al.. Hereditary thrombophilia: identification of nonsense and missense mutations in the protein C gene. Proc Natl Acad Sci U S A. 1987 May;84(9):2829-32. PMID:2437584
- ↑ Grundy C, Chitolie A, Talbot S, Bevan D, Kakkar V, Cooper DN. Protein C London 1: recurrent mutation at Arg 169 (CGG----TGG) in the protein C gene causing thrombosis. Nucleic Acids Res. 1989 Dec 25;17(24):10513. PMID:2602169
- ↑ Reitsma PH, Poort SR, Allaart CF, Briet E, Bertina RM. The spectrum of genetic defects in a panel of 40 Dutch families with symptomatic protein C deficiency type I: heterogeneity and founder effects. Blood. 1991 Aug 15;78(4):890-4. PMID:1868249
- ↑ Bovill EG, Tomczak JA, Grant B, Bhushan F, Pillemer E, Rainville IR, Long GL. Protein CVermont: symptomatic type II protein C deficiency associated with two GLA domain mutations. Blood. 1992 Mar 15;79(6):1456-65. PMID:1347706
- ↑ Grundy CB, Schulman S, Tengborn L, Kakkar VV, Cooper DN. Two different missense mutations at Arg 178 of the protein C (PROC) gene causing recurrent venous thrombosis. Hum Genet. 1992 Aug;89(6):685-6. PMID:1511989
- ↑ Gandrille S, Vidaud M, Aiach M, Alhenc-Gelas M, Fischer AM, Gouault-Heilman M, Toulon P, Fiessinger JN, Goossens M. Two novel mutations responsible for hereditary type I protein C deficiency: characterization by denaturing gradient gel electrophoresis. Hum Mutat. 1992;1(6):491-500. PMID:1301959 doi:http://dx.doi.org/10.1002/humu.1380010607
- ↑ Millar DS, Grundy CB, Bignell P, Moffat EH, Martin R, Kakkar VV, Cooper DN. A Gla domain mutation (Arg 15-->Trp) in the protein C (PROC) gene causing type 2 protein C deficiency and recurrent venous thrombosis. Blood Coagul Fibrinolysis. 1993 Apr;4(2):345-7. PMID:8499568
- ↑ Tsay W, Greengard JS, Montgomery RR, McPherson RA, Fucci JC, Koerper MA, Coughlin J, Griffin JH. Genetic mutations in ten unrelated American patients with symptomatic type 1 protein C deficiency. Blood Coagul Fibrinolysis. 1993 Oct;4(5):791-6. PMID:8292730
- ↑ Marchetti G, Patracchini P, Gemmati D, Castaman G, Rodeghiero F, Wacey A, Cooper DN, Tuddenham EG, Bernardi F. Symptomatic type II protein C deficiency caused by a missense mutation (Gly 381-->Ser) in the substrate-binding pocket. Br J Haematol. 1993 Jun;84(2):285-9. PMID:8398832
- ↑ Zheng YZ, Sakata T, Matsusue T, Umeyama H, Kato H, Miyata T. Six missense mutations associated with type I and type II protein C deficiency and implications obtained from molecular modelling. Blood Coagul Fibrinolysis. 1994 Oct;5(5):687-96. PMID:7865674
- ↑ Lind B, Schwartz M, Thorsen S. Six different point mutations in seven Danish families with symptomatic protein C deficiency. Thromb Haemost. 1995 Feb;73(2):186-93. PMID:7792728
- ↑ Ireland HA, Boisclair MD, Taylor J, Thompson E, Thein SL, Girolami A, De Caterina M, Scopacasa F, De Stefano V, Leone G, Finazzi G, Cohen H, Lane DA. Two novel (R(-11)C; T394D) and two repeat missense mutations in the protein C gene associated with venous thrombosis in six kindreds. Hum Mutat. 1996;7(2):176-9. PMID:8829639 doi:<176::AID-HUMU16>3.0.CO;2-# 10.1002/(SICI)1098-1004(1996)7:2<176::AID-HUMU16>3.0.CO;2-#
- ↑ Couture P, Demers C, Morissette J, Delage R, Jomphe M, Couture L, Simard J. Type I protein C deficiency in French Canadians: evidence of a founder effect and association of specific protein C gene mutations with plasma protein C levels. Thromb Haemost. 1998 Oct;80(4):551-6. PMID:9798967