Folding of the twisted beta-sheet in bovine pancreatic trypsin inhibitor.
Folding of the twisted beta-sheet in bovine pancreatic trypsin inhibitor.
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DOI：
10.1021/bi00348a016
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发表时间：
1985-12
期刊：
影响因子：
2.9
通讯作者：
K. Chou;G. Némethy;M. Pottle;H. Scheraga
中科院分区：
文献类型：
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作者：
K. Chou;G. Némethy;M. Pottle;H. Scheraga
在牛胰蛋白酶抑制剂中，由残基18-35组成的强扭曲反平行β -片结构的形成已证明了局部相互作用的主导作用。构象能量最小化表明，即使在没有蛋白质分子其余部分的情况下，该β -片也具有很强的扭曲。当从原始构象开始进行能量最小化时，扭转基本上保持不变。从残基18-35的非扭片构象出发，得到了一个强扭结构（比原扭结构能量更高）。天然β -片的高扭曲是其氨基酸序列的结果，但它被β -片内的链间相互作用强烈增强。扭曲-片结构的存在不需要残基14和残基38之间存在二硫键。它实际上可以促进这个键的形成。因此，β -薄片结构很可能在折叠的早期阶段形成，而不是形成这种二硫键。这项研究提供了一个例子，其中构象能计算可以用来提供有关蛋白质折叠的可能途径的信息。
The dominant role of local interactions has been demonstrated for the formation of the strongly twisted antiparallel beta-sheet structure consisting of residues 18-35 in bovine pancreatic trypsin inhibitor. Conformational energy minimization has indicated that this beta-sheet has a strong twist even in the absence of the rest of the protein molecule. The twist is maintained essentially unchanged when energy minimization is carried out by starting from the native conformation. By starting from a nontwisted beta-sheet conformation of residues 18-35, a strongly twisted structure (higher in energy than the native) is obtained. The high twist of the native-like beta-sheet is a consequence of its amino acid sequence, but it is enhanced strongly by interchain interactions that operate within the beta-sheet. The existence of the twisted beta-sheet structure does not require the presence of a disulfide bond between residue 14 and residue 38. It actually may facilitate the formation of this bond. Therefore, it is likely that the beta-sheet structure forms during an earlier stage of folding than the formation of this disulfide bond. This study provides an example of the manner in which conformational energy calculations can be used to provide information about the probable pathway of the folding of a protein.