Studies on the ultrastructure of fibrin lacking fibrinopeptide B (beta- fibrin)
Studies on the ultrastructure of fibrin lacking fibrinopeptide B (beta- fibrin)
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缺乏纤维蛋白肽B（β-纤维蛋白）的纤维蛋白超微结构研究
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发表时间：
1987
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通讯作者：
M. Samama
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作者：
M. Mosesson;J. DiOrio;M. Muller;J. Shainoff;K. Siebenlist;D. Amrani;G. Homandberg;J. Soria;C. Soria;M. Samama
铜头蛇毒液促凝血酶从纤维蛋白原中释放纤维蛋白肽 B，形成一种纤维蛋白（β 纤维蛋白），其自聚集特性比凝血酶释放纤维蛋白肽 A (FPA) 和 B (FPB) 产生的正常产物（α β 纤维蛋白）更弱。我们研究了这两种类型的纤维蛋白以及从纤维蛋白原 Metz (A α 16 Arg\---|-Cys) 制备的 β-纤维蛋白的超微结构，纤维蛋白原 Metz 是一种不释放 FPA 的纯合异常纤维蛋白发生突变体。在 14°C 和生理溶剂条件（0.15 mol/L 氯化钠、0.015 mol/L Tris 缓冲液 pH 7.4）下，快速聚合的 α-β-纤维蛋白（凝血酶 1 至 2 U/mL）的浊度（350 nm）在不到 6 分钟内达到稳定水平，并形成由吻合纤维束（平均直径 92）组成的“粗”基质。纳米）。聚合速度较慢的 αβ-纤维蛋白（凝血酶 0.01 和 0.001 U/mL）在大于或等于 60 分钟后超过了该浊度，并同时形成了较粗的纤维束网络（平均直径分别为 118 和 186 nm）。此类基质还包含高度支化、扭曲的“细”原纤维（纤维直径 7 至 30 nm）网络，这些网络通常是在高离子强度和 pH 下形成的基质的特征。缓慢聚合的β-纤维蛋白，就像缓慢聚合的α-β-纤维蛋白一样，除了底层的粗缆线网络（平均纤维直径135 nm）之外，还显示出大量的细基质，而快速聚合的β-纤维蛋白单体几乎完全由宽的、吻合不良的条纹缆线（平均直径212 nm）组成。 Metz β-纤维蛋白凝块比正常的 β-纤维蛋白凝块更脆弱，并且几乎完全由精细网络组成。然而，在生理范围内浓度（500 μmol/L）的白蛋白存在下，Metz 纤维蛋白可以被诱导形成粗纤维束（平均直径 76 nm），并且在这方面类似于 Metz 血浆纤维蛋白凝块。 Metz β-纤维蛋白形成粗纤维束的能力减弱可能是由于 FPB 释放所暴露的聚合位点的使用或占用受损所致。我们的结果表明，扭曲原纤维是所有形式的组装纤维蛋白的固有结构特征，并表明成熟的β-纤维蛋白或α-β-纤维蛋白凝块是从细原纤维网络发展而来的，这些细原纤维能够聚结形成更粗的纤维束。
Release of fibrinopeptide B from fibrinogen by copperhead venom procoagulant enzyme results in a form of fibrin (beta-fibrin) with weaker self-aggregation characteristics than the normal product (alpha beta-fibrin) produced by release of fibrinopeptides A (FPA) and B (FPB) by thrombin. We investigated the ultrastructure of these two types of fibrin as well as that of beta-fibrin prepared from fibrinogen Metz (A alpha 16 Arg\---|-Cys), a homozygous dysfibrinogenemic mutant that does not release FPA. At 14 degrees C and physiologic solvent conditions (0.15 mol/L of NaCl, 0.015 mol/L of Tris buffer pH 7.4), the turbidity (350 nm) of rapidly polymerizing alpha beta-fibrin (thrombin 1 to 2 U/mL) plateaued in less than 6 min and formed a “coarse” matrix consisting of anastomosing fiber bundles (mean diameter 92 nm). More slowly polymerizing alpha beta-fibrin (thrombin 0.01 and 0.001 U/mL) surpassed this turbidity after greater than or equal to 60 minutes and concomitantly developed a network of thicker fiber bundles (mean diameters 118 and 186 nm, respectively). Such matrices also contained networks of highly branched, twisting, “fine” fibrils (fiber diameters 7 to 30 nm) that are usually characteristic of matrices formed at high ionic strength and pH. Slowly polymerizing beta-fibrin, like slowly polymerizing alpha beta-fibrin, displayed considerable quantities of fine matrix in addition to an underlying thick cable network (mean fiber diameter 135 nm), whereas rapidly polymerizing beta-fibrin monomer was comprised almost exclusively of wide, poorly anastomosed, striated cables (mean diameter 212 nm). Metz beta-fibrin clots were more fragile than those of normal beta-fibrin and were comprised almost entirely of a fine network. Metz fibrin could be induced, however, to form thick fiber bundles (mean diameter 76 nm) in the presence of albumin at a concentration (500 mumol/L) in the physiologic range and resembled a Metz plasma fibrin clot in that regard. The diminished capacity of Metz beta-fibrin to form thick fiber bundles may be due to impaired use or occupancy of a polymerization site exposed by FPB release. Our results indicate that twisting fibrils are an inherent structural feature of all forms of assembling fibrin, and suggest that mature beta-fibrin or alpha beta-fibrin clots develop from networks of thin fibrils that have the ability to coalesce to form thicker fiber bundles.