Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA.
Biopolymers. 2011 Feb;95(2):94-104. doi: 10.1002/bip.21536. Epub 2010 Aug 24.
Collagen mimetic peptides (CMPs) have been used to elucidate the structure and stability of the triple helical conformation of collagen molecules. Although CMP homotrimers have been widely studied, very little work has been reported regarding CMP heterotrimers because of synthetic difficulties. Here, we present the synthesis and characterization of homotrimers and ABB type heterotrimers comprising natural and synthetic CMP sequences that are covalently tethered to a template, a tris(2-aminoethyl) amine (TREN) succinic acid derivative. Various tethered heterotrimers comprising synthetic CMPs [(ProHypGly)₆, (ProProGly)₆] and CMPs representing specific domains of type I collagen were synthesized and characterized in terms of triple helical structure, thermal melting behavior, and refolding kinetics. The results indicated that CMPs derived from natural type I collagen sequence can form stable heterotrimeric helical complexes with artificial CMPs and that the thermal stability and the folding rate increase with the increasing number of helical stabilizing amino acids (e.g. Hyp) in the peptide chains. Covalent tethering enhanced the thermal stability and refolding kinetics of all CMPs; however, their relative values were not affected suggesting that the tethered system can be used for comparative study of heterotrimeric CMP's folding behavior in regards to chain composition and for characterization of thermally unstable CMPs.
胶原模拟肽（CMPs）已被用于阐明胶原分子三螺旋构象的结构和稳定性。尽管 CMP 同三聚体已被广泛研究，但由于合成困难，关于 CMP 异三聚体的研究很少。在这里，我们介绍了包含天然和合成 CMP 序列的同三聚体和 ABB 型异三聚体的合成和表征，这些序列通过共价键连接到模板上，即三（2-氨基乙基）胺（TREN）琥珀酸衍生物。各种包含合成 CMPs [(ProHypGly)₆, (ProProGly)₆] 和代表 I 型胶原特定结构域的 CMP 的连接异三聚体被合成并在三螺旋结构、热熔融行为和重折叠动力学方面进行了表征。结果表明，源自天然 I 型胶原序列的 CMP 可以与人工 CMP 形成稳定的异三聚体螺旋复合物，并且随着肽链中螺旋稳定氨基酸（如 Hyp）数量的增加，热稳定性和折叠速率增加。共价键连接增强了所有 CMP 的热稳定性和重折叠动力学；然而，它们的相对值不受影响，这表明连接系统可用于比较研究异三聚体 CMP 的折叠行为，包括链组成，并用于表征热不稳定的 CMP。
