EVIDENCE FOR DISPENSABLE SEQUENCES INSERTED INTO A NUCLEOTIDE FOLD
EVIDENCE FOR DISPENSABLE SEQUENCES INSERTED INTO A NUCLEOTIDE FOLD
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DOI：
10.1126/science.3306924
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发表时间：
1987-09-25
期刊：
影响因子：
56.9
通讯作者：
SCHIMMEL, P
中科院分区：
文献类型：
--
作者：
STARZYK, RM;WEBSTER, TA;SCHIMMEL, P
以往的实验结果以及所给出的结构模型表明，大肠杆菌异亮氨酰转移RNA合成酶是一种由939个氨基酸组成的单链多肽，其氨基末端有一个核苷酸折叠。在核苷酸折叠区产生了内部缺失。一组总共跨越145个相邻氨基酸的缺失产生了活性酶。进一步延长缺失可产生不活跃或不稳定的蛋白质。一个明显同源的蛋白质的三维结构表明，活性缺失缺少连接核苷酸折叠两部分的片段。因此，结果表明，移除连接折叠这两个部分的多肽的主要部分并不会导致核苷酸结合位点的主要扰动。
Previous experimental results along with the structural modeling presented indicate that a nucleotide fold starts in the amino-terminal part of Escherichia coli isoleucyl-transfer RNA synthetase, a single chain polypeptide of 939 amino acids. Internal deletions were created in the region of the nucleotide fold. A set of deletions that collectively span 145 contiguous amino acids yielded active enzymes. Further extensions of the deletions yielded inactive or unstable proteins. The three-dimensional structure of an evidently homologous protein suggests that the active deletions lack portions of a segment that connects two parts of the nucleotide fold. Therefore, the results imply that removal of major sections of the polypeptide that connects these two parts of the fold does not result in major perturbation of the nucleotide binding site.