A new twist in the collagen story - the type VI segmented supercoil
A new twist in the collagen story - the type VI segmented supercoil
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DOI：
10.1093/emboj/20.3.372
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发表时间：
2001-02-01
期刊：
影响因子：
11.4
通讯作者：
Squire, JM
中科院分区：
文献类型：
--
作者：
Knupp, C;Squire, JM
胶原蛋白以两种主要形式存在：纤维状和非纤维状。非纤维状胶原蛋白在结构上更易变并且相对不清楚。在这项工作中，我们分析了VI型胶原蛋白的氨基酸序列，VI型胶原蛋白是一种形成反平行二聚体的非纤维状胶原蛋白，发现了一个序列基序，它引起了系统的分子卷曲。在带电荷的氨基酸、脯氨酸和Gly-X-Y三联体中的不连续性中存在共同的周期性（类似于23或2 X 23个残基）。此外，在非极性基团中存在不同的周期性（类似于21个氨基酸）。两个重复意味着在二聚体形成期间同时最大化疏水和极性相互作用的唯一方法是使分子反平行，如观察到的重叠75 nm，并且超螺旋。交替的富含脯氨酸和富含电荷的斑块，通常与Gly-X-Y序列中的不连续性一起，与超螺旋的每个半圈重合，从而将其分解成片段。我们将这种结构称为胶原分段超螺旋。分段超螺旋和变体可能是非纤维状胶原的常见聚集基序。
Collagen occurs in two major forms: fibrillar and non-fibrillar, Non-fibrillar collagens are structurally more variable and relatively ill-understood. In this work we analysed the amino acid sequence of type VI collagen, a non-fibrillar collagen that forms antiparallel dimers, A sequence motif was discovered that gives rise to systematic molecular coiling. There is a common periodicity (similar to 23 or 2 X 23 residues) in the charged amino acids, in the prolines and in the discontinuities in the Gly-X-Y triplets. In addition, there is a different periodicity (similar to 21 amino acids) in the apolar groups. The two repeats mean that the only way to simultaneously maximize both the hydrophobic and polar interactions during dimer formation is with the molecules antiparallel, overlapped by 75 nm as observed, and supercoiled, The alternating proline-rich and charge-rich patches, often together with discontinuities in the Gly-X-Y sequences, coincide with each half-turn of the supercoil, thus breaking it into segments. We have termed this structure the collagen segmented supercoil, The segmented supercoil and variants may be common aggregation motifs for the non-fibrillar collagens.