Rational Design of Single-Composition ABC Collagen Heterotrimers
Rational Design of Single-Composition ABC Collagen Heterotrimers
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DOI：
10.1021/ja209669u
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发表时间：
2012-01-25
影响因子：
15
通讯作者：
Hartgerink, Jeffrey D.
中科院分区：
文献类型：
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作者：
Fallas, Jorge A.;Lee, Michael A.;Hartgerink, Jeffrey D.
异源三聚体ABC胶原三螺旋的设计是具有挑战性的，因为可能形成大量的竞争物种。考虑到在该折叠中相邻肽链之间需要一个氨基酸交错，肽的三元混合物可以形成多达27个具有独特组成或配准的三重螺旋。以前，我们已经证明，静电相互作用可以用来偏向螺旋人口向所需的目标。然而，同三聚体组装体始终是溶液中最热稳定的物质，因此构成肽混合物的重要组分。在这项工作中，我们将互补的修改，这三螺旋设计策略，以不稳定的一个不希望的竞争状态，同时补偿这种不稳定所需的ABC组合物。这些修改的结果是一个新的ABC三螺旋系统具有高热稳定性和控制组成，如通过NMR观察到的。另外一组修饰，将天冬氨酸交换为谷氨酸，导致ABC三螺旋稳定性的总体降低，但显示系统特异性的进一步改善。这一系统的合理设计有助于阐明人工合成胶原蛋白三螺旋自组装的规律，并揭示了胶原蛋白组装的生物学机制。
Design of heterotrimeric ABC collagen triple helices is challenging due to the large number of competing species that may be formed. Given the required one amino acid stagger between adjacent peptide strands in this fold, a ternary mixture of peptides can form as many as 27 triple helices with unique composition or register. Previously we have demonstrated that electrostatic interactions can be used to bias the helix population toward a desired target. However, homotrimeric assemblies have always remained the most thermally stable species in solution and therefore comprised a significant component of the peptide mixture. In this work we incorporate complementary modifications to this triple-helical design strategy to destabilize an undesirable competing state while compensating for this destabilization in the desired ABC composition. The result of these modifications is a new ABC triple-helical system with high thermal stability and control over composition, as observed by NMR. An additional set of modifications, which exchanges aspartate for glutamate, results in an overall lowering of stability of the ABC triple helix yet shows further improvement in the system's specificity. This rationally designed system helps to elucidate the rules governing the self-assembly of synthetic collagen triple helices and sheds light on the biological mechanisms of collagen assembly.