DNA interaction and dimerization of eukaryotic SMC hinge domains
DNA interaction and dimerization of eukaryotic SMC hinge domains
复制标题
DOI：
10.1074/jbc.m402439200
复制
发表时间：
2004-06-18
影响因子：
4.8
通讯作者：
Jessberger, R
中科院分区：
文献类型：
--
作者：
Chiu, A;Revenkova, E;Jessberger, R
真核细胞中的SMC1/SMC3异源二聚体是姐妹染色单体凝聚所必需的，在DNA修复和重组中起作用。二聚化依赖于所有SMC蛋白中存在的中心铰链域，该结构域两侧各有延伸的卷曲区域，终止于特定的球状结构域。在这里，我们报道了真核细胞异源二聚体SMC1/SMC3铰链区的DNA相互作用，使用了两种已知的异构体，SMC1pha/SMC3和减数分裂SMC1beta/SMC3。这两种二聚体都倾向于结合双链DNA和富含潜在二级结构的DNA。这两个二聚体形成了庞大的蛋白质-DNA网络，并促进互补DNA链的再退火。DNA结合而不是二聚化依赖于大约20个氨基酸的螺旋卷曲区域的过渡序列。在两个铰链域中的一个上替换三个被认为是二聚化所需的高度保守的甘氨酸残基仍然可以形成稳定的二聚体，但如果两个铰链域发生突变，二聚作用就会失败。单突变二聚体结合DNA，但铰链单体不结合。总之，我们证明了真核细胞的铰链二聚不需要在两个铰链结构域上都有保守的甘氨酸，只需要过渡到卷曲区域而不是整个卷曲区域就可以与DNA结合，二聚化是真核细胞铰链异源二聚体与DNA结合所必需的，但不是充分的。
The eukaryotic SMC1/SMC3 heterodimer is essential for sister chromatid cohesion and acts in DNA repair and recombination. Dimerization depends on the central hinge domain present in all SMC proteins, which is flanked at each side by extended coiled-coil regions that terminate in specific globular domains. Here we report on DNA interactions of the eukaryotic, heterodimeric SMC1/SMC3 hinge regions, using the two known isoforms, SMC1alpha/SMC3 and the meiotic SMC1beta/SMC3. Both dimers bind DNA with a preference for double-stranded DNA and DNA rich in potential secondary structures. Both dimers form large protein-DNA networks and promote reannealing of complementary DNA strands. DNA binding but not dimerization depends on approximately 20 amino acids of transitional sequence into the coiled-coil region. Replacement of three highly conserved glycine residues, thought to be required for dimerization, in one of the two hinge domains still allows formation of a stable dimer, but if two hinge domains are mutated dimerization fails. Single-mutant dimers bind DNA, but hinge monomers do not. Together, we show that eukaryotic hinge dimerization does not require conserved glycines in both hinge domains, that only the transition into the coiled-coil region rather than the entire coiled-coil region is necessary for DNA binding, and that dimerization is required but not sufficient for DNA binding of the eukaryotic hinge heterodimer.