Characterization of monomeric L1 metallo-beta -lactamase and the role of the N-terminal extension in negative cooperativity and antibiotic hydrolysis
文献类型：期刊论文
| 作者 | Simm, Alan M; Higgins, Catherine S; Carenbauer, Anne L; Crowder, Michael W; Bateson, John H; Bennett, Peter M; Clarke, Anthony R; Halford, Stephen E; Walsh, Timothy R |
| 刊名 | The Journal of biological chemistry
 |
| 出版日期 | 2002-07-05 |
| 卷号 | 277期号:27页码:24744-52 |
| ISSN号 | 0021-9258 |
| DOI | 10.1074/jbc.M201524200 |
| 文献子类 | Article |
| 英文摘要 | The L1 metallo-beta-lactamase from Stenotrophomonas maltophilia is unique among this class of enzymes because it is tetrameric. Previous work predicted that the two regions of important intersubunit interaction were the residue Met-140 and the N-terminal extensions of each subunit. The N-terminal extension was also implicated in beta-lactam binding. Mutation of methionine 140 to aspartic acid results in a monomeric L1 beta-lactamase with a greatly altered substrate specificity profile. A 20-amino acid N-terminal deletion mutant enzyme (N-Del) could be isolated in a tetrameric form but demonstrated greatly reduced rates of beta-lactam hydrolysis and different substrate profiles compared with that of the parent enzyme. Specific site-directed mutations of individual N terminus residues were made (Y11S, W17S, and a double mutant L5A/L8A). All N-terminal mutant enzymes were tetramers and all showed higher K(m) values for ampicillin and nitrocefin, hydrolyzed ceftazidime poorly, and hydrolyzed imipenem more efficiently than ampicillin in contrast to wild-type L1. Nitrocefin turnover was significantly increased, probably because of an increased rate of breakdown of the intermediate species due to a lack of stabilizing forces. K(m) values for monomeric L1 were greatly increased for all antibiotics tested. A model of a highly mobile N-terminal extension in the monomeric enzyme is proposed to explain these findings. Tetrameric L1 shows negative cooperativity, which is not present in either the monomer or N-terminal deletion enzymes, suggesting that the cooperative effect is mediated via N-terminal intersubunit interactions. These data indicate that while the N terminus of L1 is not essential for beta-lactam hydrolysis, it is clearly important to its activity and substrate specificity. |
| 语种 | 英语 |
| 源URL | [http://119.78.100.183/handle/2S10ELR8/266651]  |
| 专题 | 中国科学院上海药物研究所 |
| 通讯作者 | Simm, Alan M |
| 作者单位 | Department of Pathology and Microbiology, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom. A.M |
| 推荐引用方式 GB/T 7714 | Simm, Alan M,Higgins, Catherine S,Carenbauer, Anne L,et al. Characterization of monomeric L1 metallo-beta -lactamase and the role of the N-terminal extension in negative cooperativity and antibiotic hydrolysis[J]. The Journal of biological chemistry,2002,277(27):24744-52. |
| APA | Simm, Alan M.,Higgins, Catherine S.,Carenbauer, Anne L.,Crowder, Michael W.,Bateson, John H.,...&Walsh, Timothy R.(2002).Characterization of monomeric L1 metallo-beta -lactamase and the role of the N-terminal extension in negative cooperativity and antibiotic hydrolysis.The Journal of biological chemistry,277(27),24744-52. |
| MLA | Simm, Alan M,et al."Characterization of monomeric L1 metallo-beta -lactamase and the role of the N-terminal extension in negative cooperativity and antibiotic hydrolysis".The Journal of biological chemistry 277.27(2002):24744-52. |
入库方式： OAI收割
来源：上海药物研究所
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