Shiba K, Schimmel P
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Proc Natl Acad Sci U S A. 1992 Mar 1;89(5):1880-4. doi: 10.1073/pnas.89.5.1880.
The sequence of a 939-amino acid polypeptide that is a member of the aminoacyl-tRNA synthetase class of enzymes has been aligned with sequences of 15 related proteins. This alignment guided the design of 18 fragment pairs that were tested for internal sequence complementarity by reconstitution of enzyme activity. Reconstitution was achieved with fragments that divide the protein at both nonconserved and conserved sequences, including locations proximal to or within elements believed to form critical elements of secondary structure. Structure assembly is sufficiently flexible to accommodate fusion of short segments of unrelated sequences at fragment junctions. Complementary chain packing interactions and chain flexibility appear to be widely distributed throughout the sequence and are sufficient to reconstruct large three-dimensional structures from an array of disconnected pieces. The results may have implications for the evolution and assembly of large proteins.
一种作为氨酰-tRNA合成酶类酶成员的939个氨基酸的多肽序列，已与15种相关蛋白质的序列进行了比对。这种比对指导了18对片段的设计，通过酶活性的重构来测试它们的内部序列互补性。在非保守序列和保守序列处分割蛋白质的片段实现了重构，包括在被认为形成二级结构关键元件的元件近端或内部的位置。结构组装具有足够的灵活性，以适应在片段连接处融合不相关序列的短片段。互补链堆积相互作用和链灵活性似乎广泛分布于整个序列中，并且足以从一系列不相连的片段重建大型三维结构。这些结果可能对大型蛋白质的进化和组装具有启示意义。
