1
|
Interplay of catalysis, fidelity, threading, and processivity in the exo- and endonucleolytic reactions of human exonuclease I. Proc Natl Acad Sci U S A 2017; 114:6010-6015. [PMID: 28533382 DOI: 10.1073/pnas.1704845114] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human exonuclease 1 (hExo1) is a member of the RAD2/XPG structure-specific 5'-nuclease superfamily. Its dominant, processive 5'-3' exonuclease and secondary 5'-flap endonuclease activities participate in various DNA repair, recombination, and replication processes. A single active site processes both recessed ends and 5'-flap substrates. By initiating enzyme reactions in crystals, we have trapped hExo1 reaction intermediates that reveal structures of these substrates before and after their exo- and endonucleolytic cleavage, as well as structures of uncleaved, unthreaded, and partially threaded 5' flaps. Their distinctive 5' ends are accommodated by a small, mobile arch in the active site that binds recessed ends at its base and threads 5' flaps through a narrow aperture within its interior. A sequence of successive, interlocking conformational changes guides the two substrate types into a shared reaction mechanism that catalyzes their cleavage by an elaborated variant of the two-metal, in-line hydrolysis mechanism. Coupling of substrate-dependent arch motions to transition-state stabilization suppresses inappropriate or premature cleavage, enhancing processing fidelity. The striking reduction in flap conformational entropy is catalyzed, in part, by arch motions and transient binding interactions between the flap and unprocessed DNA strand. At the end of the observed reaction sequence, hExo1 resets without relinquishing DNA binding, suggesting a structural basis for its processivity.
Collapse
|
2
|
Chen ZY, Zheng SR, Zhong JH, Zhuang XD, Zhou JY. Association between three exonuclease 1 polymorphisms and cancer risks: a meta-analysis. Onco Targets Ther 2016; 9:899-910. [PMID: 26966378 PMCID: PMC4770079 DOI: 10.2147/ott.s95258] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
To date, the results of studies exploring the relation between exonuclease 1 (Exo1) polymorphisms and cancer risks have differed. In this study, we performed a meta-analysis to investigate the effect of the three most extensively studied Exo1 polymorphisms (Pro757Leu, Glu589Lys, and Glu670Gly) on cancer susceptibility. The related studies published before August 5, 2015, were collected by searching the PubMed and EMBASE databases. We found 16 publications containing studies that were eligible for our study, including 10 studies for Pro757Leu polymorphism (4,093 cases and 3,834 controls), 12 studies for Glu589Lys polymorphism (6,479 cases and 6,550 controls), and 7 studies for Glu670Gly polymorphism (3,700 cases and 3,496 controls). Pooled odds ratios and 95% confidence intervals were used to assess the strength of the associations, and all the statistical analyses were calculated using the software program STATA version 12.0. Our results revealed that the Pro757Leu polymorphism was significantly associated with a reduced cancer risk, whereas an inverse association was found for the Glu589Lys polymorphism. Furthermore, subgroup analysis of smoking status indicated that the Glu589Lys polymorphism was significantly associated with an increased cancer risk in smokers, but not in nonsmokers. However, no evidence was found for an association between the Glu670Gly polymorphism and cancer risk. In conclusion, this meta-analysis suggests that the Pro757Leu polymorphism may provide protective effects against cancer, while the Glu589Lys polymorphism may be a risk factor for cancer. Moreover, the Glu670Gly polymorphism may have no influence on cancer susceptibility. In the future, large-scaled and well-designed studies are needed to achieve a more precise and comprehensive result.
Collapse
Affiliation(s)
- Zi-Yu Chen
- Department of Clinical Medicine, The First Clinical Medical College, Southern Medical University, Guangzhou, People's Republic of China; Institute of Genetic Engineering, School of Basic Medical Sciences, Southern Medical University, Guangzhou, People's Republic of China
| | - Si-Rong Zheng
- Institute of Genetic Engineering, School of Basic Medical Sciences, Southern Medical University, Guangzhou, People's Republic of China
| | - Jie-Hui Zhong
- Department of Clinical Medicine, The First Clinical Medical College, Southern Medical University, Guangzhou, People's Republic of China; Institute of Genetic Engineering, School of Basic Medical Sciences, Southern Medical University, Guangzhou, People's Republic of China
| | - Xiao-Duan Zhuang
- Department of Clinical Medicine, The First Clinical Medical College, Southern Medical University, Guangzhou, People's Republic of China; Institute of Genetic Engineering, School of Basic Medical Sciences, Southern Medical University, Guangzhou, People's Republic of China
| | - Jue-Yu Zhou
- Institute of Genetic Engineering, School of Basic Medical Sciences, Southern Medical University, Guangzhou, People's Republic of China
| |
Collapse
|
3
|
Zhang Y, Li P, Xu A, Chen J, Ma C, Sakai A, Xie L, Wang L, Na Y, Kaku H, Xu P, Jin Z, Li X, Guo K, Shen H, Zheng S, Kumon H, Liu C, Huang P. Influence of a single-nucleotide polymorphism of the DNA mismatch repair-related gene exonuclease-1 (rs9350) with prostate cancer risk among Chinese people. Tumour Biol 2015; 37:6653-9. [PMID: 26646562 DOI: 10.1007/s13277-015-4298-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 10/20/2015] [Indexed: 11/25/2022] Open
Abstract
In this study, we aimed to identify the influence of exonuclease 1 (EXO1) single-nucleotide polymorphism rs9350, which is involved in DNA mismatch repair, on prostate cancer risk in Chinese people. In our hospital-based case-control study, 214 prostate cancer patients and 253 cancer-free control subjects were enrolled from three hospitals in China. Genotyping for rs9350 was performed by the SNaPshot(®) method using peripheral blood samples. Consequently, a significantly higher prostate cancer risk was observed in patients with the CC genotype [odds ratio (OR) = 1.678, 95 % confidence interval (CI) = 1.130-2.494, P = 0.010] than in those with the CT genotype. Further, the CT/TT genotypes were significantly associated with increased prostate cancer risk (adjusted OR = 1.714, 95 % CI = 1.176-2.500, P = 0.005), and the C allele had a statistically significant compared with T allele (P = 0.009) of EXO1 (rs9350). Through stratified analysis, significant associations were revealed for the CT/TT genotype in the subgroup with diagnosis age >72 (adjusted OR = 1.776, 95 % CI = 1.051-3.002, P = 0.032) and in patients with localized disease subgroup (adjusted OR = 1.798, 95 % CI = 1.070-3.022, P = 0.027). In addition, we observed that patients with prostate-specific antigen (PSA) levels of ≤10 ng/mL were more likely to have the CT/TT genotypes than those with PSA levels of >10 ng/mL (P = 0.006). For the first time, we present evidence that the inherited EXO1 polymorphism rs9350 may have a substantial influence on prostate cancer risk in Chinese people. We believe that the rs9350 could be a useful biomarker for assessing predisposition for and early diagnosis of prostate cancer.
Collapse
Affiliation(s)
- Yiming Zhang
- Department of Urology, Zhujiang Hospital, Southern Medical University, No. 253 Gongyedadaozhong Road, Haizhu District, Guangzhou, People's Republic of China, 510282
| | - Pengju Li
- Department of Urology, Zhujiang Hospital, Southern Medical University, No. 253 Gongyedadaozhong Road, Haizhu District, Guangzhou, People's Republic of China, 510282
| | - Abai Xu
- Department of Urology, Zhujiang Hospital, Southern Medical University, No. 253 Gongyedadaozhong Road, Haizhu District, Guangzhou, People's Republic of China, 510282
| | - Jie Chen
- Department of Urology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
- Center for Innovative Clinical Medicine, Okayama University Hospital, Okayama, Japan
| | - Chao Ma
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
| | - Akiko Sakai
- Department of Molecular Genetics, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Liping Xie
- Department of Urology, The First Affiliated Hospital of Zhejiang University, Hangzhou, People's Republic of China
| | - Lei Wang
- Peking University Wu-jieping Urology Center, Peking University Shougang Hospital, Peking, People's Republic of China
| | - Yanqun Na
- Peking University Wu-jieping Urology Center, Peking University Shougang Hospital, Peking, People's Republic of China
| | - Haruki Kaku
- Department of Urology, Okamura Isshindow Hospital, Okayama, Japan
| | - Peng Xu
- Department of Urology, Zhujiang Hospital, Southern Medical University, No. 253 Gongyedadaozhong Road, Haizhu District, Guangzhou, People's Republic of China, 510282
| | - Zhong Jin
- Department of Urology, Zhujiang Hospital, Southern Medical University, No. 253 Gongyedadaozhong Road, Haizhu District, Guangzhou, People's Republic of China, 510282
| | - Xiezhao Li
- Department of Urology, Zhujiang Hospital, Southern Medical University, No. 253 Gongyedadaozhong Road, Haizhu District, Guangzhou, People's Republic of China, 510282
| | - Kai Guo
- Department of Urology, Zhujiang Hospital, Southern Medical University, No. 253 Gongyedadaozhong Road, Haizhu District, Guangzhou, People's Republic of China, 510282
| | - Haiyan Shen
- Department of Urology, Zhujiang Hospital, Southern Medical University, No. 253 Gongyedadaozhong Road, Haizhu District, Guangzhou, People's Republic of China, 510282
| | - Shaobo Zheng
- Department of Urology, Zhujiang Hospital, Southern Medical University, No. 253 Gongyedadaozhong Road, Haizhu District, Guangzhou, People's Republic of China, 510282
| | - Hiromi Kumon
- Department of Urology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
- Center for Innovative Clinical Medicine, Okayama University Hospital, Okayama, Japan
| | - Chunxiao Liu
- Department of Urology, Zhujiang Hospital, Southern Medical University, No. 253 Gongyedadaozhong Road, Haizhu District, Guangzhou, People's Republic of China, 510282.
| | - Peng Huang
- Department of Urology, Zhujiang Hospital, Southern Medical University, No. 253 Gongyedadaozhong Road, Haizhu District, Guangzhou, People's Republic of China, 510282.
- Department of Urology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
- Center for Innovative Clinical Medicine, Okayama University Hospital, Okayama, Japan.
- Okayama Medical Innovation Center, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
| |
Collapse
|