Subdomain II of alpha-Isopropylmalate Synthase Is Essential for Activity INFERRING A MECHANISM OF FEEDBACK INHIBITION
文献类型：期刊论文
| 作者 | Zhang, ZL; Wu, J; Lin, W; Wang, J; Yan, H; Zhao, W; Ma, J; Ding, JP; Zhang, P; Zhao, GP |
| 刊名 | JOURNAL OF BIOLOGICAL CHEMISTRY
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| 出版日期 | 2014 |
| 卷号 | 289期号:40页码:27966-27978 |
| 关键词 | Allosteric Regulation Cooperativity Enzyme Catalysis Enzyme Structure Protein Conformation Catalytic Module Feedback Inhibition |
| 通讯作者 | Ding, JP (reprint author), Chinese Acad Sci, Shanghai Inst Biol Sci, Inst Biochem & Cell Biol, State Key Lab Mol Biol, Shanghai 200031, Peoples R China.,jpding@sibs.ac.cn ; pengzhang01@sibs.ac.cn ; gpzhao@sibs.ac.cn |
| 英文摘要 | Background: Isopropylmalate synthases (IPMSs) with and without a regulatory domain were found. Results: IPMS subdomain II is essential for activities and likely involved in acetyl-CoA binding-mediated conformation transition. Conclusion: The N-terminal domain and the two subdomains comprise the complete and independently functional catalytic module of IPMS. Significance: The IPMS catalytic module was defined and characterized, which inferred a probable feedback inhibition mechanism. The committed step of leucine biosynthesis, converting acetyl-CoA and -ketoisovalerate into -isopropylmalate, is catalyzed by -isopropylmalate synthase (IPMS), an allosteric enzyme subjected to feedback inhibition by the end product l-leucine. We characterized the short form IPMS from Leptospira biflexa (LbIPMS2), which exhibits a catalytic activity comparable with that of the long form IPMS (LbIPMS1) and has a similar N-terminal domain followed by subdomain I and subdomain II but lacks the whole C-terminal regulatory domain. We found that partial deletion of the regulatory domain of LbIPMS1 resulted in a loss of about 50% of the catalytic activity; however, when the regulatory domain was deleted up to Arg-385, producing a protein that is almost equivalent to the intact LbIPMS2, about 90% of the activity was maintained. Moreover, in LbIPMS2 or LbIPMS1, further deletion of several residues from the C terminus of subdomain II significantly impaired or completely abolished the catalytic activity, respectively. These results define a complete and independently functional catalytic module of IPMS consisting of both the N-terminal domain and the two subdomains. Structural comparison of LbIPMS2 and the Mycobacterium tuberculosis IPMS revealed two different conformations of subdomain II that likely represent two substrate-binding states related to cooperative catalysis. The biochemical and structural analyses together with the previously published hydrogen-deuterium exchange data led us to propose a conformation transition mechanism for feedback inhibition mediated by subdomains I and II that might associated with alteration of the binding affinity toward acetyl-CoA. |
| 学科主题 | Biochemistry & Molecular Biology |
| 类目[WOS] | Biochemistry & Molecular Biology |
| 关键词[WOS] | TERMINAL REGULATORY DOMAIN ; MYCOBACTERIUM-TUBERCULOSIS ; LEPTOSPIRA-INTERROGANS ; SALMONELLA-TYPHIMURIUM ; SUBSTRATE-SPECIFICITY ; CITRAMALATE SYNTHASE ; HOMOCITRATE SYNTHASE ; CRYSTAL-STRUCTURE ; MOLECULAR-BASIS ; LEUCINE OPERON |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000342852800050 |
| 版本 | 出版稿 |
| 源URL | [http://202.127.25.143/handle/331003/271]  |
| 专题 | 上海生化细胞研究所_上海生科院生化细胞研究所 |
| 推荐引用方式 GB/T 7714 | Zhang, ZL,Wu, J,Lin, W,et al. Subdomain II of alpha-Isopropylmalate Synthase Is Essential for Activity INFERRING A MECHANISM OF FEEDBACK INHIBITION[J]. JOURNAL OF BIOLOGICAL CHEMISTRY,2014,289(40):27966-27978. |
| APA | Zhang, ZL.,Wu, J.,Lin, W.,Wang, J.,Yan, H.,...&Zhao, GP.(2014).Subdomain II of alpha-Isopropylmalate Synthase Is Essential for Activity INFERRING A MECHANISM OF FEEDBACK INHIBITION.JOURNAL OF BIOLOGICAL CHEMISTRY,289(40),27966-27978. |
| MLA | Zhang, ZL,et al."Subdomain II of alpha-Isopropylmalate Synthase Is Essential for Activity INFERRING A MECHANISM OF FEEDBACK INHIBITION".JOURNAL OF BIOLOGICAL CHEMISTRY 289.40(2014):27966-27978. |
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