Boudsocq François, Ling Hong, Yang Wei, Woodgate Roger
Section on DNA Replication, Repair and Mutagenesis, Building 6, Room 1A13, National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bethesda MD 20892-2725, USA.
DNA Repair (Amst). 2002 May 30;1(5):343-58. doi: 10.1016/s1568-7864(02)00019-8.
Our understanding of the molecular mechanisms of error-prone lesion bypass has changed dramatically in the past few years. The concept that the key participants in the mutagenic process were accessory proteins that somehow modified the ability of the cell's main replicase to facilitate bypass of normally blocking lesions has been replaced with one in which the replicase is displaced by a polymerase specialized in lesion bypass. The participants in this process remain the same, only their function has been reassigned. What was once known as the UmuC/DinB/Rev1/Rad30 superfamily of mutagenesis proteins, is now known as the Y-family of DNA polymerases. Quite remarkably, within the space of 3 years, the field has advanced from the initial discovery of intrinsic polymerase function, to the determination of the tertiary structures of several Y-family DNA polymerases.A key to determining the biochemical properties of each DNA polymerase is through structure-function studies that result in the site-specific substitution of particular amino acids at critical sites within each DNA polymerase. However, we should not forget the power of genetic selection that allows us to identify residues within each polymerase that are generated by "random mutagenesis" and which are important for both a gain or loss of function in vivo. In this review, we discuss the structural ramifications of several missense mutations previously identified in various Y-family DNA polymerase and speculate on how each amino acid substitution might modify the enzymatic activity of the respective polymerase or possibly perturb protein-protein interactions necessary for efficient translesion replication in vivo.
在过去几年里，我们对易错损伤旁路分子机制的理解发生了巨大变化。诱变过程中的关键参与者是辅助蛋白，它们以某种方式改变细胞主要复制酶绕过通常会造成阻碍的损伤的能力，这一概念已被另一种概念所取代，即复制酶被专门用于损伤旁路的聚合酶所取代。这个过程中的参与者仍然相同，只是它们的功能被重新分配了。曾经被称为诱变蛋白的UmuC/DinB/Rev1/Rad30超家族，现在被称为DNA聚合酶Y家族。非常值得注意的是，在3年的时间里，该领域从最初发现内在聚合酶功能，发展到确定几种Y家族DNA聚合酶的三级结构。确定每种DNA聚合酶生化特性的关键是通过结构-功能研究，这种研究导致在每种DNA聚合酶关键位点进行特定氨基酸的位点特异性替换。然而，我们不应忘记遗传筛选的作用，它使我们能够识别每种聚合酶中由“随机诱变”产生的残基，这些残基对于体内功能的获得或丧失都很重要。在这篇综述中，我们讨论了先前在各种Y家族DNA聚合酶中鉴定出的几种错义突变的结构影响，并推测每种氨基酸替换可能如何改变相应聚合酶的酶活性，或可能扰乱体内有效跨损伤复制所需的蛋白质-蛋白质相互作用。
