THE SACCHAROMYCES-CEREVISIAE MSH2 PROTEIN SPECIFICALLY BINDS TO DUPLEX OLIGONUCLEOTIDES CONTAINING MISMATCHED DNA-BASE PAIRS AND INSERTIONS
THE SACCHAROMYCES-CEREVISIAE MSH2 PROTEIN SPECIFICALLY BINDS TO DUPLEX OLIGONUCLEOTIDES CONTAINING MISMATCHED DNA-BASE PAIRS AND INSERTIONS
复制标题
DOI：
10.1101/gad.9.2.234
复制
发表时间：
1995-01-15
影响因子：
10.5
通讯作者：
KOLODNER, R
中科院分区：
文献类型：
--
作者：
ALANI, E;CHI, NW;KOLODNER, R
酿酒酵母编码的四种蛋白质Msh1、Msh2、Msh3、Msh4与细菌MutS错配修复系统的中心成分MutS具有很强的氨基酸序列相似性。MutS已被证明在体外识别DNA中的碱基对错配。以往的研究表明，Msh2是酵母中主要的错配识别蛋白。在本研究中，我们对109-kD的Msh2多肽进行了高效表达和纯化，以分析其与DNA的结合特性。这一分析表明，Msh2可以选择性地与含有G/T错配、1到14个核苷酸插入错配和回文(12到14个核苷酸)插入错配的双链寡核苷酸底物结合。总的趋势是Msh2对底物的亲和力与插入错对的大小成正比(+14PAL，+12PAL；+14；+8；GT，+6，+4，+2，+1)。动力学研究表明，Msh2对错配底物的特异性是它与含有错配的双链DNA形成稳定络合物的能力的函数。这些复合体比与同源双链DNA形成的Msh2复合体的衰变更慢。
The yeast Saccharomyces cerevisiae encodes four proteins, Msh1, Msh2, Msh3, Msh4, that show strong amino acid sequence similarity to MutS, a central component of the bacterial mutHLS mismatch repair system. MutS has been shown to recognize base pair mismatches in DNA in vitro. Previous studies have suggested that Msh2 is the major mismatch recognition protein in yeast. In this study, the 109-kD Msh2 polypeptide was overexpressed and purified to analyze its DNA-binding properties. This analysis demonstrated that Msh2 can bind selectively to duplex oligonucleotide substrates containing a G/T mismatch, 1- to 14-nucleotide insertion mismatches, and palindromic (12- to 14-nucleotide) insertion mismatches. A general trend was that the affinity of Msh2 for substrate was proportional to the size of the insertion mispair present (+14 PAL, +12 PAL>+14>+8>GT, +6, +4, +2, +1). Kinetic studies indicated that the specificity of Msh2 to mismatch substrates was a function of its ability to form stable complexes with mispair-containing duplex DNAs. These complexes decayed more slowly than Msh2 complexes formed with homoduplex DNA.