大肠杆菌DNA聚合酶III、dnaZ蛋白以及DNA延伸因子I和III催化的DNA延伸机制。
Mechanism of DNA elongation catalyzed by Escherichia coli DNA polymerase III, dnaZ protein, and DNA elongation factors I and III.
作者信息
Wickner S
出版信息
Proc Natl Acad Sci U S A. 1976 Oct;73(10):3511-5. doi: 10.1073/pnas.73.10.3511.
Elongation of a primed single-stranded DNA template catalyzed by E. coli DNA polymerase III (DNA nucleotidyltransferase, deoxynucleosidetriphosphate:DNA deoxynucleotidyltransferase, EC 2.7.7.7) requires dnaZ protein and two other protein factors, DNA elongation factors I and III. The reaction occurs by the following mechanism: (i) dnaZ protein and DNA elongation factor III together catalyze the transfer of DNA elongation factor I to a primed DNA template. This transfer reaction requires ATP or dATP in addition to dnaZ protein, DNA elongation factors I and III, and primed template; it does not require DNA polymerase III. (ii) DNA polymerase III binds to the complex of DNA elongation factor I with primed template; it does not bind to primed template which is not complexed with DNA elongation factor I. This binding reaction proceeds in the absence of ATP or dATP as cofactor, dnaZ protein, and DNA elongation factor III and without additional DNA elongation factor I. (iii) The complex of DNA polymerase III, DNA elongation factor I, and primed template catalyzes DNA synthesis upon the addition of dNTPs.
由大肠杆菌DNA聚合酶III（DNA核苷酸转移酶，脱氧核苷三磷酸：DNA脱氧核苷酸转移酶，EC 2.7.7.7）催化的引发单链DNA模板的延伸需要dnaZ蛋白和另外两种蛋白质因子，即DNA延伸因子I和III。该反应通过以下机制发生：（i）dnaZ蛋白和DNA延伸因子III共同催化DNA延伸因子I转移到引发的DNA模板上。除了dnaZ蛋白、DNA延伸因子I和III以及引发模板外，这种转移反应还需要ATP或dATP；它不需要DNA聚合酶III。（ii）DNA聚合酶III与DNA延伸因子I和引发模板的复合物结合；它不与未与DNA延伸因子I复合的引发模板结合。这种结合反应在没有ATP或dATP作为辅因子、dnaZ蛋白和DNA延伸因子III的情况下进行，并且不需要额外的DNA延伸因子I。（iii）DNA聚合酶III、DNA延伸因子I和引发模板的复合物在添加dNTPs后催化DNA合成。
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