Abstract
In an abnormal fibrinogen with impaired fibrin monomer polymerization designed as fibrinogen Osaka II, we have identified substitution of Arg by Cys at position 275 of the gamma chain. This Cys is linked to a free cysteine molecule by a disulfide link as evidenced by fast atom bombardment mass spectrometry. This finding was supported by identification of a single cysteine released from isolated abnormal fragment D1 upon reduction. This unique cystine structure at the mutation site has not been reported heretofore in any abnormal protein including fibrinogen. The substitution may well perturb the structure required for fibrin monomer polymerization, specifically that assigned to the carboxyl-terminal D domain of fibrinogen. Indeed, isolated fragment D1 with the Cys substitution failed to inhibit thrombin-mediated clotting of normal fibrinogen and normal fibrin monomer polymerization, while normal fragment D1 inhibited them markedly. Our data seem to provide supporting evidence that the putative polymerization site(s) assigned to the D domain of fibrinogen may be structure-dependent, including the carboxyl-terminal segment of the gamma chain as well as a contiguous region that contains the gamma 275 residue.
Highlights
Introduction11, we have identified substitution ofArgbyCysat the carboxyl-terminal region of the y chain [8,9]
**Departmentof Biology, Faculty of Science, Kyushu University, Fukuoka 812, Japan, and the $$Division of Biophysics, Institute for Protein Research, Osaka University, Suita, Osaka 612, Japan
By peptide mapping of pyridylethylated y chain (Pe-y), we identified an aberrant peptide peak denoted as K26‘ (Fig. 5, panel B ), which is missing in normal Pe-y digests (Fig. 5p, anel A ) .Based onthe amino-terminal sequence data, this peptide was identified as the7274-302 peptide segment
Summary
11, we have identified substitution ofArgbyCysat the carboxyl-terminal region of the y chain [8,9]. Thfisind- To better understand the mechanisms of fibrin monomer ing was supportedby identification of a single cysteine polymerization, congenital dysfibrinogens with clearly elucirtnmtrmiheeooaodelrneynumacoscswamaitetirledoeeblpnrlhofr.prxaopTooystemlhelnyr-iittnmosueitusrreibonmbnrlecitiazieqhlntuanueeadtsdeirDltioarencbnupdygn,coossftotrmpiuitrbneermarcedeiiirnanfshelitofqcerorgaruuafeelicgnltrfytmo.eiubftdTreohrfenrhioanetretaofitiansgbutsehraDsbniienns.lgytmniIutnaeupudbdtot-ieanote-ond,ppocdyfaraAoIistrnevtreigdindtdheefs,iittseibor.vuerpii.cCndaatpeyumfnesrrrcoae,aeelnatwotcbhpmeynaosoerttsererimptiptinhoooaeerlnlytCimtmiay2oens7esle5rsaidcuzbuoebafnlssteeiot,torirhbtvnmuyeedtaiacuyolnaenfrcaitebiohdfsruadailliniintnsoip.tkoguoFenediudannyrltt.twdohimiesatruhu,hltfaiaimwldtfiee--on isolated fragment Dl with the Cys substitution failed bond. To our knowledge, such a cystine structurehasnot to inhibit thrombin-mediatedclottingof normal fibrin- been reported heretofore in any hereditary abnormal plasma ogenandnormaflibrinmonomerpolymerization, protein, including fibrinogen, a plasma protein, alwhile normal fragmentDl inhibited them markedly. EXPERIMENTALPROCEDURES cluding the carboxyl-terminal segment of they chain as well as a contiguous region that contains the 7275
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
