3-DIMENSIONAL STRUCTURE OF THE BETA-SUBUNIT OF ESCHERICHIA-COLI DNA POLYMERASE-III HOLOENZYME - A SLIDING DNA CLAMP
3-DIMENSIONAL STRUCTURE OF THE BETA-SUBUNIT OF ESCHERICHIA-COLI DNA POLYMERASE-III HOLOENZYME - A SLIDING DNA CLAMP
复制标题
DOI：
10.1016/0092-8674(92)90445-i
复制
发表时间：
1992-05-01
期刊：
影响因子：
64.5
通讯作者：
KURIYAN, J
中科院分区：
文献类型：
--
作者：
KONG, XP;ONRUST, R;KURIYAN, J
DNA聚合酶III全酶的β-亚基（持续合成因子）的晶体结构已在2.5埃分辨率下测定。β-亚基的二聚体（M（r）= 2 x 40.6 kd，2 x 366个氨基酸残基）形成由12-α-螺旋排列的环形结构，可以包围双链DNA。该结构是高度对称的，每个单体含有三个相同拓扑结构的结构域。螺旋的电荷分布和方向表明，分子通过形成一个可以在DNA上滑动的紧密夹来发挥作用，如生物化学所示。β亚基和增殖细胞核抗原（PCNA，真核生物聚合酶-δ [和PCNA]合成因子）与噬菌体T4 DNA聚合酶的基因45蛋白之间存在潜在的结构关系。
The crystal structure of the beta-subunit (processivity factor) of DNA polymerase III holoenzyme has been determined at 2.5 angstrom resolution. A dimer of the beta-subunit (M(r) = 2 x 40.6 kd, 2 x 366 amino acid residues) forms a ring-shaped structure lined by 12-alpha-helices that can encircle duplex DNA. The structure is highly symmetrical, with each monomer containing three domains of identical topology. The charge distribution and orientation of the helices indicate that the molecule functions by forming a tight clamp that can slide on DNA, as shown biochemically. A potential structural relationship is suggested between the beta-subunit and proliferating cell nuclear antigen (PCNA, the eukaryotic polymerase-delta [and epsilon] processivity factor), and the gene 45 protein of the bacteriophage T4 DNA polymerase.