Analysis of Aα251 fibrinogen:: The αC domain has a role in polymerization, albeit more subtle than anticipated from the analogous proteolytic fragment x
Analysis of Aα251 fibrinogen:: The αC domain has a role in polymerization, albeit more subtle than anticipated from the analogous proteolytic fragment x
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DOI：
10.1021/bi981551t
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发表时间：
1998-11-03
期刊：
影响因子：
2.9
通讯作者：
Lord, ST
中科院分区：
文献类型：
--
作者：
Gorkun, OV;Henschen-Edman, AH;Lord, ST
大量实验证明，纤维蛋白原A α链的C端结构域，即α C结构域，在聚合中具有作用。为了进一步研究该结构域的作用，我们合成了一种缺乏α C结构域的重组纤维蛋白原，A α 251纤维蛋白原。我们检查了凝血酶催化的纤维蛋白肽释放，发现 A α 251 纤维蛋白原释放 FpB 的速率比正常纤维蛋白原释放 FpB 的速率慢 2.5 倍，而两种蛋白的 FpA 释放速率相同。我们检查了凝血酶催化的聚合，发现两种蛋白质的原纤维形成和横向聚集的速率相似，尽管横向聚集的明显差异是明显的。 A α 251 纤维蛋白原的原纤维形成率不低于正常纤维蛋白原的 85%，而 A α 251 纤维蛋白原的横向聚集率从正常情况的 64% 到 74% 不等。我们检查了纤维蛋白单体的聚合，发现 A α 251 纤维蛋白的聚合在 0.4 M NaCl 下与正常纤维蛋白相似，但在 0.4 M NaCl 下与正常纤维蛋白明显不同。 0.05 M 氯化钠。这些结果表明 α C 结构域在横向聚集中发挥作用，但这种作用比以前的实验预期的更微妙，特别是那些具有纤维蛋白原片段 X 的实验，我们将这一意外发现解释为表明 β 链 N 末端的重要贡献，使得包括少量缺乏 β 链 N 末端的纤维蛋白的蛋白质异质性导致显着 改变横向聚集。
Numerous experiments have demonstrated that the C-terminal domain of the fibrinogen A alpha-chain, the alpha C domain, has a role in polymerization, To further examine the role of this domain, we synthesized a recombinant fibrinogen, A alpha 251 fibrinogen, that lacks the alpha C domain. We examined thrombin-catalyzed fibrinopeptide release and found that the rate of FpB release from A alpha 251 fibrinogen was 2.5-fold slower than FpB release from normal fibrinogen, while the rate of FpA release was the same for both proteins. We examined thrombin-catalyzed polymerization and found that the rates of protofibril formation and lateral aggregation were similar for both proteins, although discernible differences in lateral aggregation were clear. The rate of protofibril formation for A alpha 251 fibrinogen was never less than 85% of normal fibrinogen, while the rate of lateral aggregation for A alpha 251 fibrinogen varied from 64 to 74% of normal, We examined polymerization of fibrin monomers and found that polymerization of A alpha 251 fibrin was similar to normal fibrin at 0.4 M NaCl, but clearly different from normal at 0.05 M NaCl. These results indicate that the alpha C domain has a role in lateral aggregation, but this role is more subtle than anticipated from previous experiments, particularly those with fibrinogen fragment X, We interpret this unanticipated finding as indicative of an important contribution from the N-terminus of the beta-chain, such that protein heterogeneity that includes small amounts of fibrin lacking that N-terminus of the beta-chain leads to markedly altered lateral aggregation.