Site-directed mutants of human RECQ1 reveal functional importance of the zinc binding domain.
Site-directed mutants of human RECQ1 reveal functional importance of the zinc binding domain.
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人RECQ1的位置突变体揭示了锌结合结构域的功能重要性。
DOI：
10.1016/j.mrfmmm.2016.05.005
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发表时间：
2016-08
期刊：
影响因子：
--
通讯作者：
Sharma S
中科院分区：
文献类型：
--
作者：
Sami F;Gary RK;Fang Y;Sharma S
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RecQ helicases are a highly conserved family of ATP-dependent DNA-unwinding enzymes with key roles in DNA replication and repair in all kingdoms of life. The RECQ1 gene encodes the most abundant RecQ homolog in humans. Mutations in RECQ1 significantly increase breast cancer susceptibility. We engineered full-length RECQ1 harboring point mutations in the zinc-binding motif (amino acids 419–480) within the conserved RecQ-specific-C-terminal (RQC) domain known to be critical for diverse biochemical and cellular functions of RecQ helicases. Wild-type RECQ1 contains a zinc ion. Substitution of three of the four conserved cysteine residues that coordinate zinc severely impaired the ATPase and DNA unwinding activities but retained DNA binding and single strand DNA annealing activities. Furthermore, alteration of these residues attenuated zinc binding and significantly changed the overall conformation of full-length RECQ1 protein. In contrast, substitution of cysteine residue at position 471 resulted in a wild-type like RECQ1 protein. Differential contribution of the conserved cysteine residues to the structure and functions of the RECQ1 protein is also inferred by homology modeling. Overall, our results indicate that the zinc binding motif in the RQC domain of RECQ1 is a key structural element that is essential for the structure-functions of RECQ1. Given the recent association of RECQ1 mutations with breast cancer, these observations will contribute to understanding the molecular basis of RECQ1 functions in cancer etiology.