期刊
NATURE STRUCTURAL & MOLECULAR BIOLOGY
卷 23, 期 5, 页码 402-408出版社
NATURE PUBLISHING GROUP
DOI: 10.1038/nsmb.3207
关键词
-
资金
- US National Institutes of Health [GM032431]
- US-Israel Binational Science Foundation [2013358]
- Directorate for STEM Education
- Division Of Undergraduate Education [2013358] Funding Source: National Science Foundation
DNA polymerase delta (Pol delta) is responsible for elongation and maturation of Okazaki fragments. Pol 8 and the flap endonuclease FEN1, coordinated by the PCNA clamp, remove RNA primers and produce ligatable nicks. We studied this process in the Saccharomyces cerevisiae machinery at millisecond resolution. During elongation, PCNA increased the Pol 8 catalytic rate by >30-fold. When Pol delta invaded double-stranded RNA-DNA representing unmatured Okazaki fragments, the incorporation rate of each nucleotide decreased successively to 10-20% that of the preceding nucleotide. Thus, the nascent flap acts as a progressive molecular brake on the polymerase, and consequently FEN1 cuts predominantly single-nucleotide flaps. Kinetic and enzyme trapping experiments support a model in which a stable PCNA-DNA-Pol delta-FEN1 complex moves processively through iterative steps of nick translation, ultimately completely removing primer RNA. Finally, whereas elongation rates are under dynamic dNTP control, maturation rates are buffered against changes in dNTP concentrations.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据