Yang W, Chan V C, Kirkpatrick A, Ramshaw J A, Brodsky B
Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey 08854-5636, USA.
J Biol Chem. 1997 Nov 14;272(46):28837-40. doi: 10.1074/jbc.272.46.28837.
A set of host-guest peptides of the form Ac(Gly-Pro-Hyp)3-Gly-X-Y-(Gly-Pro-Hyp)4-Gly-Gly-NH2 has been designed to evaluate the propensity of different Gly-X-Y triplets for the triple-helix conformation (Shah, N. K., Ramshaw, J. A. M., Kirkpatrick, A., Shah, C., and Brodsky, B. (1996) Biochemistry 35, 10262-10268). All Gly-X-Y guest triplets led to a decrease in melting temperature from the host (Gly-Pro-Hyp)8 peptide except for Gly-Pro-Arg. In this Gly-Pro-Hyp-rich environment, Gly-Pro-Arg was found to be as stabilizing as Gly-Pro-Hyp. Decreased stability of host-guest peptides containing Gly-Pro-Lys, Gly-Pro-homo-Arg, and Gly-Arg-Hyp compared with Gly-Pro-Arg indicated a stabilization that is optimal for Arg and specific to the Y-position. Arg was found to have a similar stabilizing effect when residues other than Pro are in the X-position. Both Arg and Hyp stabilize the triple-helix preferentially in the Y-position in a stereospecific manner and occupy largely Y-positions in collagen. However, contiguous Gly-Pro-Hyp units are highly stable and promote triple-helix folding, whereas incorporation of multiple Gly-Pro-Arg triplets was destabilizing and folded slowly due to charge repulsion. In collagen, Gly-Pro-Arg may contribute maximally to local triple-helix stability while also having the potential for electrostatic interactions in fibril formation and binding.
已设计出一组形式为Ac(Gly-Pro-Hyp)3-Gly-X-Y-(Gly-Pro-Hyp)4-Gly-Gly-NH2的主客体肽，以评估不同Gly-X-Y三联体形成三螺旋构象的倾向（沙阿，N.K.，拉姆肖，J.A.M.，柯克帕特里克，A.，沙阿，C.，和布罗德斯基，B.（1996年）《生物化学》35卷，10262 - 10268页）。除了Gly-Pro-Arg外，所有Gly-X-Y客体三联体都会导致主体（Gly-Pro-Hyp）8肽的解链温度降低。在这种富含Gly-Pro-Hyp的环境中，发现Gly-Pro-Arg与Gly-Pro-Hyp一样具有稳定作用。与Gly-Pro-Arg相比，含有Gly-Pro-Lys、Gly-Pro-高精氨酸和Gly-Arg-Hyp的主客体肽稳定性降低，这表明精氨酸对稳定作用是最佳的且对Y位具有特异性。当X位为除脯氨酸以外的残基时，发现精氨酸具有类似的稳定作用。精氨酸和羟脯氨酸都以立体特异性方式优先在Y位稳定三螺旋，并且在胶原蛋白中主要占据Y位。然而，连续的Gly-Pro-Hyp单元非常稳定并促进三螺旋折叠，而多个Gly-Pro-Arg三联体的掺入由于电荷排斥而导致不稳定且折叠缓慢。在胶原蛋白中，Gly-Pro-Arg可能对局部三螺旋稳定性贡献最大，同时在原纤维形成和结合中也具有静电相互作用的潜力。
