1rf0

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1rf0, resolution 2.81Å ()
Ligands: ,
Gene: FGA (Homo sapiens), FGB (Homo sapiens), FGG (Homo sapiens)
Related: 1lt9, 1ltj, 1re3, 1re4, 1fzg, 1fzc, 1rf1
Resources: FirstGlance, OCA, RCSB, PDBsum
Coordinates: save as pdb, mmCIF, xml


Contents

Crystal Structure of Fragment D of gammaE132A Fibrinogen

Publication Abstract from PubMed

Structural analysis of recombinant fibrinogen fragment D revealed that the calcium-binding site (beta2-site) composed of residues BbetaAsp261, BbetaAsp398, BbetaGly263, and gammaGlu132 is modulated by the "B:b" interaction. To determine the beta2-site's role in polymerization, we engineered variant fibrinogen gammaE132A in which calcium binding to the beta2-site was disrupted by replacing glutamic acid at gamma132 with alanine. We compared polymerization of gammaE132A to normal fibrinogen as a function of calcium concentration. Polymerization of gammaE132A at concentrations of calcium <or=1 mM exhibited an uncharacteristic 2-3-fold increase in lateral aggregation and fiber thickness compared to normal fibrinogen, while polymerization of variant and normal were indistinguishable at 10 mM calcium. These results suggest that the beta2-site controls the extent of lateral aggregation. That is, when the calcium anchor (beta2-site) is eliminated before "B:b" interactions occur then lateral aggregation is enhanced. We solved structures of fragment D of gammaE132A fibrinogen (rfD-gammaE132A) with and without Gly-His-Arg-Pro-amide (GHRPam) and found no change to the global structure. X-ray diffraction data showed GHRPam binding in the "a" and "b" polymerization sites and that calcium could still bind to the beta2-site of gammaE132A fibrinogen at 70 mM calcium. We found that the gamma2 calcium-binding site (in loop gamma294-301) did not have calcium bound in the structure of fragment D of gammaE132A fibrinogen with GHRPam bound (rfD-gammaE132A+GH). Analysis of structures rfD-gammaE132A+GH and rfD-BbetaD398A+GH indicated that differences in calcium occupation of the gamma2-site resulted from minor conformational changes provoked by crystal packing and GHRPam binding to the "a" site did not directly modulate calcium binding to this site.

Calcium-binding site beta 2, adjacent to the "b" polymerization site, modulates lateral aggregation of protofibrils during fibrin polymerization., Kostelansky MS, Lounes KC, Ping LF, Dickerson SK, Gorkun OV, Lord ST, Biochemistry. 2004 Mar 9;43(9):2475-83. PMID:14992585

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

Disease

[FIBA_HUMAN] Defects in FGA are a cause of congenital afibrinogenemia (CAFBN) [MIM:202400]. This is a rare autosomal recessive disorder characterized by bleeding that varies from mild to severe and by complete absence or extremely low levels of plasma and platelet fibrinogen. Note=The majority of cases of afibrinogenemia are due to truncating mutations. Variations in position Arg-35 (the site of cleavage of fibrinopeptide a by thrombin) leads to alpha-dysfibrinogenemias. Defects in FGA are a cause of amyloidosis type 8 (AMYL8) [MIM:105200]; also known as systemic non-neuropathic amyloidosis or Ostertag-type amyloidosis. AMYL8 is a hereditary generalized amyloidosis due to deposition of apolipoprotein A1, fibrinogen and lysozyme amyloids. Viscera are particularly affected. There is no involvement of the nervous system. Clinical features include renal amyloidosis resulting in nephrotic syndrome, arterial hypertension, hepatosplenomegaly, cholestasis, petechial skin rash.[1] [FIBG_HUMAN] Defects in FGG are a cause of congenital afibrinogenemia (CAFBN) [MIM:202400]. This rare autosomal recessive disorder is characterized by bleeding that varies from mild to severe and by complete absence or extremely low levels of plasma and platelet fibrinogen. Note=Patients with congenital fibrinogen abnormalities can manifest different clinical pictures. Some cases are clinically silent, some show a tendency toward bleeding and some show a predisposition for thrombosis with or without bleeding. [FIBB_HUMAN] Defects in FGB are a cause of congenital afibrinogenemia (CAFBN) [MIM:202400]. This rare autosomal recessive disorder is characterized by bleeding that varies from mild to severe and by complete absence or extremely low levels of plasma and platelet fibrinogen. Note=Patients with congenital fibrinogen abnormalities can manifest different clinical pictures. Some cases are clinically silent, some show a tendency toward bleeding and some show a predisposition for thrombosis with or without bleeding.

Function

[FIBA_HUMAN] Fibrinogen has a double function: yielding monomers that polymerize into fibrin and acting as a cofactor in platelet aggregation. [FIBG_HUMAN] Fibrinogen has a double function: yielding monomers that polymerize into fibrin and acting as a cofactor in platelet aggregation. [FIBB_HUMAN] Fibrinogen has a double function: yielding monomers that polymerize into fibrin and acting as a cofactor in platelet aggregation.

About this Structure

1rf0 is a 6 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA.

See Also

Reference

  • Kostelansky MS, Lounes KC, Ping LF, Dickerson SK, Gorkun OV, Lord ST. Calcium-binding site beta 2, adjacent to the "b" polymerization site, modulates lateral aggregation of protofibrils during fibrin polymerization. Biochemistry. 2004 Mar 9;43(9):2475-83. PMID:14992585 doi:http://dx.doi.org/10.1021/bi0359978
  1. Benson MD, Liepnieks J, Uemichi T, Wheeler G, Correa R. Hereditary renal amyloidosis associated with a mutant fibrinogen alpha-chain. Nat Genet. 1993 Mar;3(3):252-5. PMID:8097946 doi:http://dx.doi.org/10.1038/ng0393-252

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