Characterization of Metallo-B-Lactamases

超出所提供的空间。细菌对抗生素的耐药性是当今生物医学中最重要的问题之一。最常用的处方抗生素是含有β-内酰胺的化合物，如青霉素和头孢菌素，这是由于它们的有效性、生产成本和相对低的副作用。大多数情况下，细菌通过产生β-内酰胺酶而对这些抗生素产生耐药性，β-内酰胺酶水解并降解抗生素。一组特别令人不安的β-内酰胺酶含有1-2个Zn（II）离子，称为金属β-内酰胺酶（MbL）。MbL目前由至少25种不同的细菌菌株产生，并且这些酶水解所有已知的含有β-内酰胺的抗生素，包括抑制丝氨酸活性位点β-内酰胺酶的化合物。生物化学和结构研究表明，存在三种不同的MbL，这些差异表明，针对一种MbL的抑制剂可能不会抑制另一种MbL。本提案中描述的策略涉及表征来自每种不同类别的酶的MbL，确定酶的共同结构和机制方面，并基于这些共同特征设计抑制剂。来自嗜麦芽窄食单胞菌、脆弱拟杆菌和温和气单胞菌的MbL将使用动力学、光谱和生物化学研究来表征。本研究的具体目标是（1）探测底物结合，（2）探测反应机理，（3）继续努力制备这些酶的抑制剂。这些研究的结果将允许更全面地了解这些临床重要酶的结构和机制，特别是可用于设计或重新设计抑制剂的酶。相关性：细菌对抗生素的耐药性是快速出现的医学问题，其中最近可治疗的细菌感染不再对抗生素敏感。这些拟议研究的结果应允许制备新的药物，当与目前可用的抗生素联合使用时，将有效治疗耐药性细菌感染。性能现场=

EXCEED THE SPACE PROVIDED. Bacterial resistance to antibiotics is one of the most important problems in biomedicine today. The most commonly prescribed antibiotics are beta-lactam containing compounds, such as the penicillins and cephalosporins, due to their effectiveness, production costs, and relative low side effects. Most often, bacteria become resistant to these antibiotics by producing beta-lactamases, which hydrolyze and inactivate the antibiotics. One particularly troubling group of beta-lactamases contains 1-2 Zn(ll) ions and are called metallo-beta-lactamases (MbL's). MbL's are currently produced by at least 25 different bacterial strains, and these enzymes hydrolyze all known beta-lactam containing antibiotics, including the compounds that inhibit the serine active site beta-lactamases. Biochemical and structural studies have demonstrated that there are three distinct classes of MbL's, and these differences suggest that an inhibitor against one MbL may not inhibit another MbL. The strategy described in this proposal involves characterization of a MbL from each of the distinct classes of enzymes, identifying common structural and mechanistic aspects of the enzymes, and designing inhibitors based on those common features. The MbL's from Stenotrophomonas maltophilia, Bacteroides fragilis, and Aeromonas sobria will be characterized using kinetic, spectroscopic, and biochemical studies. The specific aims of this proposed research are (1) to probe substrate binding, (2) to probe the reaction mechanism, and (3) to continue efforts to prepare inhibitors of these enzymes. The results from these studies will allow for a more complete understanding of the structure and mechanism of these clinically-important enzymes specifically that can be used to design or redesign inhibitors. Relevance: Bacterial resistance to antibiotics is rapidly-emerging medical problem in which bacterial infections that were recently treatable are no longer susceptible to antibiotics. Results from these proposed studies should allow for the preparation of new drugs, when given in combination with currently available antibiotics will be effective in treating antibiotic-resistant bacterial infections. PERFORMANCE SITE ========================================Section End===========================================