Mutagenesis of the HMGB (high-mobility group B) protein Cmb1 (cytosine-mismatch binding 1) of Schizosaccharomyces pombe:: effects on recognition of DNA mismatches and damage
Mutagenesis of the HMGB (high-mobility group B) protein Cmb1 (cytosine-mismatch binding 1) of Schizosaccharomyces pombe:: effects on recognition of DNA mismatches and damage
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DOI：
10.1042/bj20021506
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发表时间：
2003-06-01
影响因子：
4.1
通讯作者：
Fleck, O
中科院分区：
文献类型：
--
作者：
Kunz, C;Zurbriggen, K;Fleck, O
Cmb 1（cytosine-mismatch binding 1）是粟酒裂殖酵母的一种高迁移率族（HMG）蛋白，由223个氨基酸组成，在C末端具有一个HMG结构域。我们已经创建了Cmb 1蛋白的几种突变体和缺失形式，并研究了对一般DNA结合和与DNA错配和受损DNA的特异性结合的影响。Cmb 1Delta 41（即Cmb 1，其中41个N-末端氨基酸已被删除）特异性结合含胞嘧啶的错配，顺铂诱导的链内交联顺式-GG和顺式-AG和O-6-甲基鸟嘌呤损伤。DNA结合不受影响时，45个N-末端氨基酸被删除，但被废除的情况下的50个N-末端氨基酸，并减少Cmb 1被截短5至11个C-末端氨基酸。在95 ℃加热后，C-mb 1（有和没有C-末端截短）保留了其DNA结合亲和力。在S.用顺铂处理粟酒酵母细胞。有丝分裂突变率在S. pombe cmb 1无效突变体和cmb 1-（1-212）突变体，其编码缺少11个C-末端氨基酸的Cmb 1蛋白。我们的结论是避免突变Cmb 1是不同的Msh 2依赖的错配修复，但有关核苷酸切除修复。
Cmb1 (cytosine-mismatch binding 1) is a high-mobility group (HMG) protein of Schizosaccharomyces pombe, which consists of 223 amino acids and has a single HMG domain at the C-terminal end. We have created several mutant and deletion forms of the Cmb1 protein and studied the effects on general DNA binding and specific binding to DNA mismatches and damaged DNA. Cmb1Delta41 (i.e. Cmb 1 from which the 41 N-terminal amino acids have been deleted) bound specifically to cytosine-containing mismatches, to the cisplatin-induced intrastrand cross-links cis-GG and cis-AG and to an O-6-methylguanine lesion. DNA binding was not affected when the 45 N-terminal amino acids were deleted, but was abolished in the absence of the 50 N-terminal amino acids, and was reduced when Cmb1 was truncated by between five and eleven C-terminal amino acids. C-mb1, both with and without the C-terminal truncations, retained its DNA binding affinity after heating at 95 degreesC. The cmb1 gene was induced when S. pombe cells were treated with cisplatin. Mitotic mutation rates were increased in a S. pombe cmb1 null mutant and in a cmb1-(1-212) mutant, which encodes a Cmb1 protein lacking the 11 C-terminal amino acids. We conclude that mutation avoidance by Cmb1 is distinct from Msh2-dependent mismatch repair, but related to nucleotide excision repair.