STRUCTURAL PRINCIPLES OF ALPHA-BETA-BARREL PROTEINS - THE PACKING OF THE INTERIOR OF THE SHEET
STRUCTURAL PRINCIPLES OF ALPHA-BETA-BARREL PROTEINS - THE PACKING OF THE INTERIOR OF THE SHEET
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DOI：
10.1002/prot.340050208
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发表时间：
1989-01-01
影响因子：
2.9
通讯作者：
CHOTHIA, C
中科院分区：
文献类型：
--
作者：
LESK, AM;BRANDEN, CI;CHOTHIA, C
.alpha. /度量。桶状结构与最初在磷酸三糖异构酶中观察到的非常相似，现在已知在14种酶中存在桶状结构。为了了解这种折叠的起源，我们分析了其中三种蛋白质中八链β的几何结构。-片材和在桶中央的残留物的包装。在乙醇酸氧化酶中，这个区域的堆积以其最简单的形式出现。它由排列在三层中的12个残基组成。每一层包含四个侧链。RubisCO和TIM的堆积可以通过这种简单模式的扭曲来理解，这是由在桶内某些位置具有小侧链的残基引起的。有两类包装。在RubisCO和TIM所属的一类中，中心层由第一、第三、第五和第七链的残基组成；上层和下层由第二、第四、第六和第八股的残基形成。在GAO所属的第二类中，情况正好相反：来自偶数链的侧链形成了中间层，而来自奇数链的侧链形成了外层。我们的研究结果表明，并不是所有具有这种折叠的蛋白质都与进化有关，但它们代表了一种共同的有利解决方案，以解决产生封闭β蛋白所涉及的结构问题。桶。
.alpha./.beta. barrel structures very similar to that first observed in triose phosphate isomerase are now known to occur in 14 enzymes. To understand the origin of this fold, we analyzed in three of these proteins the geometry of the eight-stranded .beta.-sheets and the packing of the residues at the center of the barrel. The packing in this region in seen in its simplest form in glycolate oxidase. It consists of 12 residues arranged in three layers. Each layer contains four side chains. The packing of RubisCO and TIM can be understood in terms of distortions of this simple pattern, caused by residues with small side chains at some of the positions inside the barrel. Two classes of packing are found. In one class, to which RubisCO and TIM belong, the central layer is formed by a residue from the first, third, fifth, and seventh strands; the upper and lower layers are formed by residues from the second, fourth, sixth, and eighth strands. In the second class, to which GAO belongs, this is reversed: it is side chains from the even-numbered strands that form the central layer, and side chains from the odd-numbered strands that form the outer layers. Our results suggest that not all proteins with this fold are related by evolutions, but that they represent a common favorable solution to the structural problems involved in the creation of a closed .beta. barrel.