Zagari A, Némethy G, Scheraga H A
Dipartimento di Chimica, Università di Napoli, Italy.
Biopolymers. 1990;30(9-10):967-74. doi: 10.1002/bip.360300911.
The chemical and biological properties of collagen are altered by the biosynthetic substitution of the L-azetidine-2-carboxylic acid(Aze) residue in the place of proline. The reasons for this alteration have been studied by means of conformational energy computations on single- and triple-stranded structures formed by poly(Gly-X-Y) poly(tripeptide)s, where X and Y can be Pro or Aze. The most stable triple helix formed by Poly(Gly-Pro-Aze) is collagen-like, but all low-energy triple helices that can be formed by poly(Gly-Aze-Pro) and poly(Gly-Aze-Aze) are very different from collagen. Thus, the regular substitution of Aze for Pro in position X is not compatible with the collagen structure. In the absence of solvent effects, all of these triple helices are stable, relative to the statistical coil, but the substitutions reduce the stability of the collagen-like triple helix, as compared with poly(Gly-Pro-Pro).
通过用L-氮杂环丁烷-2-羧酸（Aze）残基取代脯氨酸进行生物合成取代，胶原蛋白的化学和生物学特性发生了改变。通过对由聚（Gly-X-Y）聚三肽形成的单链和三链结构进行构象能计算，研究了这种改变的原因，其中X和Y可以是脯氨酸或Aze。由聚（Gly-Pro-Aze）形成的最稳定三螺旋是类胶原的，但聚（Gly-Aze-Pro）和聚（Gly-Aze-Aze）能形成的所有低能三螺旋都与胶原非常不同。因此，在X位置用Aze常规取代脯氨酸与胶原结构不兼容。在没有溶剂效应的情况下，相对于统计线圈，所有这些三螺旋都是稳定的，但与聚（Gly-Pro-Pro）相比，这些取代降低了类胶原三螺旋的稳定性。
