The high binding affinity of human ribosomal protein S3 to 7,8-dihydro-8-oxoguanine is abrogated by a single amino acid change
The high binding affinity of human ribosomal protein S3 to 7,8-dihydro-8-oxoguanine is abrogated by a single amino acid change
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DOI：
10.1016/j.dnarep.2006.04.001
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发表时间：
2006-07-13
期刊：
影响因子：
3.8
通讯作者：
Deutsch, Walter A.
中科院分区：
文献类型：
--
作者：
Heyde, Vijay;Wanyb, Mu;Deutsch, Walter A.
先前的研究表明，人核糖体蛋白S3（hS 3）对DNA中的7，8-二氢-8-氧代鸟嘌呤（8-oxoG）残基具有高的表观结合亲和力，并与人碱基切除修复（BER）蛋白OGG 1和APE/Ref-1相互作用。我们使用计算和实验方法的组合来理解hS 3在BER中的作用及其阻碍OGG 1和APE/Ref-1修复8-oxoG损伤的潜力。采用序列分析来鉴定可能参与与8-oxoG结合的hS 3残基。位于螺旋-发夹-螺旋DNA结合基序中的一个推定位点赖氨酸132（K132）突变为丙氨酸（K132 A）。hS 3-K132 A突变体保留了切割脱碱基DNA的能力，但其结合8-oxoG的能力被完全消除。还测试了OGGl切割与hS 3或hS 3-K132 A预孵育的8-oxoG-寡核苷酸底物的能力。用野生型hS 3和含有8-oxoG的寡核苷酸预孵育完全阻止了随后通过OGGl去除8-oxoG。另一方面，与hS 3-K132 A组合的OGGl孵育刺激了超过两倍的8-oxoG的切割，证实了先前的观察结果，即hS 3与OGGl正相互作用，但仅在hS 3与8-oxoG的结合受限的条件下。总的来说，当hS 3与8-oxoG位点结合时，OGG 1修复8-oxoG的能力受到损害。相反，在不存在DNA结合的情况下，hS 3与OGG 1积极相互作用，以产生DNA中8-oxoG残基的更稳健的去除。(c)2006 Elsevier B. V.保留所有权利。
Previous studies have shown that human ribosomal protein S3 (hS3) has a high apparent binding affinity for 7,8-dihydro-8-oxoguanine (8-oxoG) residues in DNA and interacts with the human base excision repair (BER) proteins OGG1 and APE/Ref-1. We used a combination of computational and experimental approaches to understand the role of hS3 in BER and its potential to hinder repair of 8-oxoG lesions by OGG1 and APE/Ref-1. Sequence analysis was employed to identify hS3 residues likely to be involved in binding to 8-oxoG. One putative site, lysine 132 (K132), located in a helix-hairpin-helix DNA binding motif, was mutated to alanine (K132A). The hS3-K132A mutant retained the ability to cleave abasic DNA, but its capacity to bind 8-oxoG was abrogated completely The ability of OGG1 to cleave an 8-oxoG-oligonucleotide substrate pre-incubated with hS3 or hS3-K132A was also tested. Pre-incubations with wild-type hS3 and 8-oxoG- containing oligonucleotides completely prevented the subsequent removal of 8-oxoG by OGG1. On the other hand, OGG1 incubations combined with hS3-K132A stimulated cleavage of 8-oxoG in excess of two-fold, confirming previous observations that hS3 positively interacts with OGG1, but only under conditions in which the binding of hS3 to 8-oxoG is limited. Overall, the ability of OGG1 to repair 8-oxoG is compromised when hS3 is bound to 8-oxoG sites. Conversely, in the absence of DNA binding, hS3 interacts positively with OGG1 to produce a more robust removal of 8-oxoG residues in DNA. (c) 2006 Elsevier B.V. All rights reserved.