Protein splicing of yeast VMA1-derived endonuclease via thiazolidine intermediates
Protein splicing of yeast VMA1-derived endonuclease via thiazolidine intermediates
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DOI：
10.1107/s0909049503023495
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发表时间：
2004-01-01
影响因子：
2.5
通讯作者：
Satow, Y
中科院分区：
文献类型：
--
作者：
Mizutani, R;Anraku, Y;Satow, Y
蛋白质剪接精确地从蛋白质前体切除内部内含肽片段，并伴随连接内含肽侧翼的N-和C-末端外显肽多肽。制备了含有N-和C-外显肽多肽的重组X10 SNS，用于来自酿酒酵母VMA 1基因的内含肽内切核酸酶。X10 SNS取代了C284 S、H362 N和C738 S，并在晶格中形成内含肽和外显肽片段。X10 SNS的晶体结构揭示了N-和C-外显肽片段之间的连接，并表明所得内含肽片段的C284氨基与N-外显肽片段的G283 0原子相互作用。最后的S -> N酰基转移步骤的机理提出，四面体中间体涉及在G283-C738连接处的五元噻唑烷环。噻唑烷中间体的含氧阴离子通过C284 N原子稳定。
Protein splicing precisely excises out an internal intein segment from a protein precursor, and concomitantly ligates the N- and C-terminal extein polypeptides flanking the intein. A recombinant X10SNS bearing N- and C-extein polypeptides has been prepared for the intein endonuclease derived from the Saccharomyces cerevisiae VMA1 gene. X10SNS has replacements of C284S, H362N, and C738S, and forms the intein and extein segments in the crystal lattice. The crystal structure of X10SNS revealed a linkage between the N- and C-extein segments, and showed that the C284 amino group of the resultant intein segment is in interaction with the G283 0 atom of the N-extein segment. A mechanism for the final S --> N acyl shift step proposes that a tetrahedral intermediate involves a five-memberred thiazolidine ring at G283-C738 junction. An oxyanion of the thiazolidine intermediate is to be stabilized by the C284 N atom.