3f6u is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
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.[1][2][3][4][5][6][7][8][9][10][11][12][13][14] 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.
Function
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.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The serine protease domain of activated protein C (APC) contains a Na+ and a Ca2+ site. However, the number and identity of the APC residues that coordinate to Na+ is not precisely known. Further, the functional link between the Na+ and the Ca2+ site is insufficiently defined, and their linkage to the substrate S1 site has not been studied. Here, we systematically investigate the functional significance of these two cation sites and their thermodynamic links to the S1 site. Kinetic data reveal that Na+ binds to the substrate-occupied APC with K(d) values of approximately 24 mm in the absence and approximately 6 mm in the presence of Ca2+. Sodium-occupied APC has approximately 100-fold increased catalytic efficiency ( approximately 4-fold decrease in K(m) and approximately 25-fold increase in k(cat)) in hydrolyzing S-2288 (H-d-Ile-Pro-Arg-p-nitroanilide) and Ca2+ further increases this k(cat) slightly ( approximately 1.2-fold). Ca2+ binds to the protease domain of APC with K(d) values of approximately 438 microm in the absence and approximately 105 microm in the presence of Na+. Ca2+ binding to the protease domain of APC does not affect K(m) but increases the k(cat) approximately 10-fold, and Na+ further increases this k(cat) approximately 3-fold and decreases the K(m) value approximately 3.7-fold. In agreement with the K(m) data, sodium-occupied APC has approximately 4-fold increased affinity in binding to p-aminobenzamidine (S1 probe). Crystallographically, the Ca2+ site in APC is similar to that in trypsin, and the Na+ site is similar to that in factor Xa but not thrombin. Collectively, the Na+ site is thermodynamically linked to the S1 site as well as to the protease domain Ca2+ site, whereas the Ca2+ site is only linked to the Na+ site. The significance of these findings is that under physiologic conditions, most of the APC will exist in Na2+-APC-Ca2+ form, which has 110-fold increased proteolytic activity.
Thermodynamic linkage between the S1 site, the Na+ site, and the Ca2+ site in the protease domain of human activated protein C (APC). Sodium ion in the APC crystal structure is coordinated to four carbonyl groups from two separate loops.,Schmidt AE, Padmanabhan K, Underwood MC, Bode W, Mather T, Bajaj SP J Biol Chem. 2002 Aug 9;277(32):28987-95. Epub 2002 May 23. PMID:12029084[15]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
↑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:https://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
↑Schmidt AE, Padmanabhan K, Underwood MC, Bode W, Mather T, Bajaj SP. Thermodynamic linkage between the S1 site, the Na+ site, and the Ca2+ site in the protease domain of human activated protein C (APC). Sodium ion in the APC crystal structure is coordinated to four carbonyl groups from two separate loops. J Biol Chem. 2002 Aug 9;277(32):28987-95. Epub 2002 May 23. PMID:12029084 doi:10.1074/jbc.M201892200
