Sequence dependence of the folding of collagen-like peptides - Single amino acids affect the rate of triple-helix nucleation
Sequence dependence of the folding of collagen-like peptides - Single amino acids affect the rate of triple-helix nucleation
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DOI：
10.1074/jbc.274.12.7668
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发表时间：
1999-03-19
影响因子：
4.8
通讯作者：
Brodsky, B
中科院分区：
文献类型：
--
作者：
Ackerman, MS;Bhate, M;Brodsky, B
研究了包埋在共同宿主框架中的一组21个客体三联体的热变性模型胶原样肽的重折叠：乙酰基（Gly-Pro-Hyp）（3）-Gly-Xaa-Yaa-（Gly-Pro-Hyp）（4）-Gly结果显示折叠速率对客体Gly-Xaa-Yaa三联体的身份有很强的依赖性，复性的半衰期为6 - 110分钟（浓度= 1 mg/ml）。Gly-Xaa-Hyp形式的所有三联体促进快速折叠，其速率仅略微依赖于Xaa位置中的残基。相比之下，Gly-Pro-Yaa和Gly-Xaa-Yaa形式的三联体较慢，并且显示出宽范围的半衰期，随着三联体中残基的身份而变化。在低浓度下，折叠可以用三级动力学描述，表明成核是限速的。不同Gly-Xaa-Yaa三联体的相对成核能力的数据支持亚氨基酸的有利性质、羟脯氨酸的重要性、相同残基在Xaa位置与Yaa位置的不同影响以及亮氨酸或天冬氨酸在Yaa位置时遇到的困难。不同三肽序列促进肽中三螺旋成核的相对倾向的信息将有助于鉴定胶原序列中的成核位点。
The refolding of thermally denatured model collagenlike peptides was studied for a set of 21 guest triplets embedded in a common host framework: acetyl-(Gly-Pro-Hyp)(3)-Gly-Xaa-Yaa-(Gly-Pro-Hyp)(4)-Gly The results show a strong dependence of the folding rate on the identity of the guest Gly-Xaa-Yaa triplet, with the half-times for refolding varying from 6 to 110 min (concentration = 1 mg/ml). All triplets of the form Gly-Xaa-Hyp promoted rapid folding, with the rate only marginally dependent on the residue in the Xaa position. In contrast, triplets of the form Gly-Pro-Yaa and Gly-Xaa-Yaa were slower and showed a wide range of half-times, varying with the identity of the residues in the triplet. At low concentrations, the folding can be described by third-order kinetics, suggesting nucleation is rate-limiting. Data on the relative nucleation ability of different Gly-Xaa-Yaa triplets support the favorable nature of imino acids, the importance of hydroxyproline, the varying effects of the same residue in the Xaa position versus the Yaa position, and the difficulties encountered when leucine or aspartic acid are in the Yaa position. Information on the relative propensities of different tripeptide sequences to promote nucleation of the triple-helix in peptides will aid in identification of nucleation sites in collagen sequences.