Structural maintenance of chromosomes protein C-terminal domains bind preferentially to DNA with secondary structure
Structural maintenance of chromosomes protein C-terminal domains bind preferentially to DNA with secondary structure
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DOI：
10.1074/jbc.273.37.24088
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发表时间：
1998-09-11
影响因子：
4.8
通讯作者：
Jessberger, R
中科院分区：
文献类型：
--
作者：
Akhmedov, AT;Frei, C;Jessberger, R
染色体结构维持蛋白（SMC）在染色体凝聚、姐妹染色单体内聚、DNA重组和基因剂量补偿等方面与DNA相互作用。单个SMC蛋白及其功能域如何结合DNA尚未被描述。我们证明了酿酒酵母snell和SMC2蛋白的c端结构域的能力，代表了两个具有不同功能的主要亚家族，以atp独立的方式结合DNA。观察到三种水平的DNA结合特异性：I)双链well -sus单链DNA的偏好为100倍；2)对能够形成二级结构的DNA片段和合成的十字形DNA分子具有高亲和力；3)对特定类型的富含at的DNA片段的强烈偏好，这些片段包括来自支架相关区域的片段，以及与各种其他聚合物相反的交替聚（dT-dA）聚（dT-dA）合成聚合物。互补DNA链的再退火也主要由c端结构域促进。与它们的体外DNA结合活性一致，我们发现SMC C端过表达会增加质粒损失，但不会改变细胞活力或细胞周期进程。
Structural maintenance of chromosomes (SMC) proteins interact with DNA in chromosome condensation, sister chromatid cohesion, DNA recombination, and gene dosage compensation. How individual SMC proteins and their functional domains bind DNA has not been described. We demonstrate the ability of the C-terminal domains of Saccharomyces cerevisiae snarl and SMC2 proteins, representing two major subfamilies with different functions, to bind DNA in an ATP-independent manner. Three levels of DNA binding specificity were observed: I) a >100-fold preference for double-stranded vel-sus single-stranded DNA; 2) a high affinity for DNA fragments able to form secondary structures and for synthetic cruciform DNA molecules; and 3) a strong preference for AT-rich DNA fragments of particular types, These include fragments from the scaffold-associated regions, and an alternating poly(dT-dA)poly(dT-dA) synthetic polymer, as opposed to a variety of other polymers. Reannealing of complementary DNA strands is also promoted primarily by the C-terminal domains. Consistent with their in vitro DNA binding activity, we show that overexpression of the SMC C termini increases plasmid loss without altering viability or cell cycle progression.