Coacervation is promoted by molecular interactions between the PF2 segment of fibrillin-1 and the domain 4 region of tropoelastin
Coacervation is promoted by molecular interactions between the PF2 segment of fibrillin-1 and the domain 4 region of tropoelastin
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DOI：
10.1021/bi050530d
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发表时间：
2005-08-02
期刊：
影响因子：
2.9
通讯作者：
Weiss, AS
中科院分区：
文献类型：
--
作者：
Clarke, AW;Wise, SG;Weiss, AS
在形成弹性纤维时，微纤丝充当用于沉积弹性蛋白前体原弹性蛋白的支架位点。我们研究了通过凝聚促进大量弹性蛋白原缔合的关键结合相互作用。使用已知结合全长原弹性蛋白的微原纤维蛋白PF 2的片段，我们将其相互作用位点映射到由结构域2和18所限定的原弹性蛋白的N-末端区域。通过转氨酶交联和质谱的新组合发现了原弹性蛋白的结构域4和Escherin-1的结构域16之间的精确接触残基，其中接触位点在原弹性蛋白的残基K38和Escherin-1的Q669处。这是第一次报告的作用，该地区的原弹性蛋白在微纤维的相互作用。PF 2的加入在热力学上促进了原弹性蛋白的凝聚，导致凝聚系统的熵和焓值的较小变化。一种新的多组分体外弹性蛋白原组装反应系统表明，积累的弹性蛋白原在空间上和优先定向到PF 2包被的表面，如组织弹性发生期间有组织的三维分布所预期的。这项研究强调了在弹性纤维组装的初始阶段，在微纤维-弹性蛋白连接处，这部分的弹性蛋白-1作为原弹性蛋白的锚点的作用。
In forming elastic fibers, microfibrils act as the scaffold sites for depositing the elastin precursor tropoelastin. We examined key binding interactions that promote massive tropoelastin association through coacervation. Using a segment of the microfibril protein fibrillin-1, PF2, known to bind full-length tropoelastin, we mapped its interaction site to the N-terminal region of tropoelastin bounded by domains 2 and 18. Precise contact residues between domain 4 of tropoelastin and domain 16 of fibrillin-1 were discovered through a novel combination of transglutaminase cross-linking and mass spectroscopy, with contact sites at residues K38 of tropoelastin and Q669 of fibrillin-1. This is the first report of a role for this region of tropoelastin in microfibril interactions. The addition of PF2 thermodynamically facilitated the coacervation of tropoelastin, resulting in smaller changes in entropy and enthalpy values for the coacervating system. A novel multicomponent in vitro tropoelastin assembly reaction system demonstrated that amassed tropoelastin was spatially and preferentially directed to surfaces coated with PF2 as expected for organized three-dimensional distribution during tissue elastogenesis. This study underscores the role of this part of fibrillin-1 as an anchor point for tropoelastin at the microfibril-elastin junction during the initial stages of elastic fiber assembly.