Biochemical analysis of the DNA unwinding and strand annealing activities catalyzed by human RECQ1
Biochemical analysis of the DNA unwinding and strand annealing activities catalyzed by human RECQ1
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DOI：
10.1074/jbc.m500264200
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发表时间：
2005-07-29
影响因子：
4.8
通讯作者：
Brosh, RM
中科院分区：
文献类型：
--
作者：
Sharma, S;Sommers, JA;Brosh, RM
RecQ解旋酶在保持基因组完整性方面起着重要的作用，它们在DNA修复、重组和复制中的细胞作用也引起了人们的极大兴趣。在已确定的五种人类RecQ解旋酶中，有三种与以癌症发病率或过早衰老为特征的遗传疾病有关：沃纳综合征、布鲁姆综合征和罗斯蒙德-汤姆森综合征。虽然Werner综合征和Bloom综合征中的WRN和BLM解旋酶的生化特性和蛋白质相互作用已被广泛研究，但对其他人类RecQ解旋酶的功能了解较少。我们将注意力集中在人类RECQ1上，这是一种DNA解旋酶，其细胞功能在很大程度上仍未确定。在这项工作中，我们表征了RECQ1催化的DNA高效解离所需的DNA底物特异性和最佳辅因子要求，并确定了RECQ1具有不同于其他RecQ解旋酶的某些性质。RECQ1稳定地与各种DNA结构结合，使其能够解开一组不同的DNA底物。除了DNA结合和解旋酶活性外，RECQ1还催化互补单链DNA分子之间的高效链退火。RECQ1促进链退火的能力受ATP结合的调节，从而导致蛋白质的构象变化。RECQ1解旋酶的酶性质和链退火活性在所提出的细胞DNA代谢途径的背景下进行了讨论，这些途径在维持基因组稳定性方面是重要的。
RecQ helicases play an important role in preserving genomic integrity, and their cellular roles in DNA repair, recombination, and replication have been of considerable interest. Of the five human RecQ helicases identified, three are associated with genetic disorders characterized by an elevated incidence of cancer or premature aging: Werner syndrome, Bloom syndrome, and Rothmund-Thomson syndrome. Although the biochemical properties and protein interactions of the WRN and BLM helicases defective in Werner syndrome and Bloom syndrome, respectively, have been extensively investigated, less information is available concerning the functions of the other human RecQ helicases. We have focused our attention on human RECQ1, a DNA helicase whose cellular functions remain largely uncharacterized. In this work, we have characterized the DNA substrate specificity and optimal cofactor requirements for efficient RECQ1-catalyzed DNA unwinding and determined that RECQ1 has certain properties that are distinct from those of other RecQ helicases. RECQ1 stably bound to a variety of DNA structures, enabling it to unwind a diverse set of DNA substrates. In addition to its DNA binding and helicase activities, RECQ1 catalyzed efficient strand annealing between complementary single-stranded DNA molecules. The ability of RECQ1 to promote strand annealing was modulated by ATP binding, which induced a conformational change in the protein. The enzymatic properties of the RECQ1 helicase and strand annealing activities are discussed in the context of proposed cellular DNA metabolic pathways that are important in the maintenance of genomic stability.