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标题：Evidence for S-nitrosothiol-dependent changes in fibrinogen that do not involve transnitrosation or thiolation
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作者：Shirin Akhter ; Arianna Vignini ; Zhong Wen 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2002
卷号：99
期号：14
页码：9172-9177
DOI：10.1073/pnas.142136499
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：S-nitrosoglutathione (GSNO, 50 {micro}M) inhibited the initial rate of thrombin-catalyzed human and bovine fibrinogen polymerization by {approx}50% to 68% respectively. Inhibition was also observed with other structurally varied S-nitrosothiols (RSNOs) including sugar derivatives of S-nitroso-N-acetylpenicillamine (SNAP). The fact that the same concentration of GSNO had no effect on thrombin-dependent hydrolysis of tosylglycylprolylarginine-4-nitroanilide acetate suggested that this inhibition was due to GSNO-induced changes in fibrinogen structure. This result was confirmed by CD spectroscopy where GSNO or S-nitrosohomocysteine increased the -helical content of fibrinogen by {approx}15% and 11%, respectively. S-carboxymethylamido derivatives of glutathione or homocysteine had no effect on the fibrinogen secondary structure. The GSNO-dependent secondary structural effects were reversed on gel filtration chromatography, suggesting that the effects were allosteric. Further evidence for fibrinogen-GSNO interactions was obtained from GSNO-dependent quenching of the intrinsic fibrinogen Trp fluorescence and the perturbation of the GSNO circular dichroic absorbance as a function of [fibrinogen]. The Kds of 3 to 10 {micro}M for fibrinogen-GSNO interactions with a stoichiometry of 2:1 (GSNO:fibrinogen) were estimated from isothermal titration calorimetry and fluorescence quenching, respectively. These results suggest that RSNOs induce changes to fibrinogen structure by interacting at specific aromatic rich domains. Three such putative RSNO-binding domains have been identified in the unordered, aromatic residue-rich C-termini of the -chains of fibrinogen.