2OYI

Crystal Structure of Fragment D of gammaD298,301A Fibrinogen with the Peptide Ligand Gly-Pro-Arg-Pro-Amide

Summary for 2OYI

• Entry DOI: 10.2210/pdb2oyi/pdb
• Related: 1FZG 1JY2 1LT9 1LTJ 1RE3 1RE4 1RF0 2FFD 2OYH
• Descriptor: Fibrinogen alpha chain, Fibrinogen beta chain, Fibrinogen gamma chain, ... (7 entities in total)
• Functional Keywords: blood clotting, fibrinogen, fibrinogen fragment d, variant fibrinogen, gammad298, 301a fibrinogen
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 10
• Total formula weight: 160641.79

Authors

Kostelansky, M.S.,Gorkun, O.V.,Lord, S.T. (deposition date: 2007-02-22, release date: 2007-05-15, Last modification date: 2024-10-30)

Primary citation

Kostelansky, M.S.,Lounes, K.C.,Ping, L.F.,Dickerson, S.K.,Gorkun, O.V.,Lord, S.T.
Probing the gamma2 Calcium-Binding Site: Studies with gammaD298,301A Fibrinogen Reveal Changes in the gamma294-301 Loop that Alter the Integrity of the "a" Polymerization Site.
Biochemistry, 46:5114-5123, 2007

PubMed Abstract: To determine the significance of the gamma2 calcium-binding site in fibrin polymerization, we synthesized the fibrinogen variant, gammaD298,301A. We expected these two alanine substitutions to prevent calcium binding in the gamma2 site. We examined the influence of calcium on the polymerization of gammaD298,301A fibrinogen, evaluated its plasmin susceptibility, and solved 2.7 and 2.4 A crystal structures of the variant with the peptide ligands Gly-Pro-Arg-Pro-amide (GPRP) and Gly-His-Arg-Pro-amide (GHRP), respectively. We found that thrombin-catalyzed polymerization of gammaD298,301A fibrinogen was modestly impaired, whereas batroxobin-catalyzed polymerization was significantly impaired relative to normal fibrinogen. Notably, the influence of calcium on polymerization was the same for the variant and for normal fibrinogen. Fibrinogen gammaD298,301A was more susceptible to plasmin proteolysis in the presence of GPRP. This finding suggests structural changes in the near-by "a" polymerization site. Comparisons of the structures revealed minor conformational changes in the gamma294-301 loop that are likely responsible for the weakened "a" site. When considered altogether, the data suggest that the gamma2 calcium-binding site does not significantly modulate polymerization. We cannot, however, rule out the possibility that the weakened "a" polymerization site masks an important role for the gamma2 calcium-binding site in normal polymerization. Somewhat unexpectedly, the structure data showed that GPRP bound to the "b" site and induced the same local conformational changes as GHRP to this site. This structure shows that "A:b" interactions can occur and suggests that these may participate in normal polymerization.

PubMed: 17411074
DOI: 10.1021/bi602607a

Experimental method

X-RAY DIFFRACTION (2.7 Å)