STRUCTURAL AND FUNCTIONAL SIMILARITIES OF PROKARYOTIC AND EUKARYOTIC DNA-POLYMERASE SLIDING CLAMPS
STRUCTURAL AND FUNCTIONAL SIMILARITIES OF PROKARYOTIC AND EUKARYOTIC DNA-POLYMERASE SLIDING CLAMPS
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DOI：
10.1093/nar/23.18.3613
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发表时间：
1995-09-25
影响因子：
14.9
通讯作者：
ODONNELL, M
中科院分区：
文献类型：
--
作者：
KELMAN, Z;ODONNELL, M
细胞复制型DNA聚合酶的非凡持续合成能力来自于它们对DNA的有力控制，这种控制来自于一种环状蛋白质，它包围着DNA并将聚合酶束缚在染色体上。原核生物原型“滑动夹”的晶体结构尽管β是二聚体，PCNA是三聚体，但它们的结构几乎是可重叠的。即使它们不是六聚体，滑动夹具有由包含每个β单体的三个球状结构域和包含每个PCNA单体的两个结构域产生的假6重对称性，这些结构域具有相同的链折叠，并且在三维空间中几乎相同。来自不同生物体的11个β和13个PCNA蛋白的氨基酸序列已经被比对和研究，以进一步了解这些滑动夹的结构和功能之间的关系。此外，假定的PCNA的胚胎形式是β的大小，因此可以像原核生物夹一样包围DNA作为二聚体。
The remarkable processivity of cellular replicative DNA polymerases derive their fight grip to DNA from a ring-shaped protein that encircles DNA and tethers the polymerase to the chromosome. The crystal structures of prototypical 'sliding clamps' of prokaryotes (beta subunit) and eukaryotes (PCNA) are ring shaped proteins for encircling DNA, Although beta is a dimer and PCNA is a trimer, their structures are nearly superimposable, Even though they are not hexamers, the sliding clamps have a pseudo 6-fold symmetry resulting from three globular domains comprising each beta monomer and two domains comprising each PCNA monomer, These domains have the same chain fold and am nearly identical in three-dimensions. The amino acid sequences of 11 beta and 13 PCNA proteins from different organisms have been aligned and studied to gain further insight into the relation between the structure and function of these sliding clamps, Furthermore, a putative embryonic form of PCNA is the size of beta and thus may encircle DNA as a dimer like the prokaryotic clamps.