Positive and Negative Design Leads to Compositional Control in AAB Collagen Heterotrimers
Positive and Negative Design Leads to Compositional Control in AAB Collagen Heterotrimers
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DOI：
10.1021/ja111239r
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发表时间：
2011-04-13
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：
O'Leary, Lesley E. R.;Fallas, Jorge A.;Hartgerink, Jeffrey D.
虽然胶原蛋白是人体中含量最丰富的蛋白质，至少有28种类型，但涉及胶原蛋白模拟系统的研究直到最近才开始考虑胶原蛋白固有的控制螺旋组成和注册的能力。胶原蛋白三螺旋可以是同三聚体或异三聚体，虽然某些类型的天然胶原蛋白只形成一种特定的螺旋组成，但其他类型的胶原可以形成多个组成。如果可能，充分了解并复制天然胶原对螺旋组成和注册的控制是至关重要的。在这篇文章中，我们利用正负设计来组装特定的AAB杂三聚体，利用带电氨基酸形成螺旋内的静电相互作用，促进杂三聚体的形成，同时抑制同源三聚体的形成。减少羟脯氨酸含量会进一步抑制同源三聚体的形成，否则会导致三螺旋形成的非特异性促进。我们以2：1的比例组合多肽，其中丰度较高的多肽具有1/2的电荷，而丰度较低的多肽相反，这可以导致形成两性中性的AAB杂三聚体。使用这种方法，我们能够设计完全控制所产生的三螺旋的组成的胶原蛋白模拟系统。所有先前关于合成胶原蛋白杂三聚体的报道都表明，由于残留的同源三聚体的量不同，在组成方面存在混合种群。我们的结果对胶原蛋白序列的自组装有了更好的理解，同时也为合成细胞外基质模拟物提供了一种新的设计方案，无论是正向的还是负向的。
Although collagen is the most abundant protein in the human body and has at least 28 types, research involving collagen mimetic systems only recently began to consider the innate ability of collagen to control helix composition and register. Collagen triple helices can be homotrimeric or heterotrimeric, and while some types of natural collagen form only one specific composition of helix, others can form multiple compositions. It is critical to fully understand and, if possible, reproduce the control that native collagen has on helix composition and register. In this Article, we utilize both positive and negative design for the assembly of specific AAB heterotrimers using charged amino acids to form intrahelix electrostatic interactions, which promote heterotrimer formation and simultaneously discourage homotrimers. Homotrimers are further discouraged by reducing hydroxyproline content, which would otherwise lead to nonspecific promotion of triple helix formation. We combine peptides in a 2:1 ratio in which the more abundant peptide has a charge 1/2 and opposite of the less abundant peptide, which can result in the formation of a zwitterionically neutral AAB heterotrimer. Using this approach, we are able to design collagen mimetic systems with full control over the composition of the resulting triple helix. All previous reports on synthetic collagen heterotrimers have shown mixed populations with respect to composition due to varying amounts of residual homotrimers. Our results yield a greater understanding of the self-assembly of collagenous sequences as well as provide a novel design scheme, both positive and negative, for the synthesis of extracellular matrix mimetics.