Class A Carbapenemases

描述（由申请人提供）：A类碳青霉烯酶与其他耐药机制结合能够对几乎所有现有抗生素产生耐药性，并对成功治疗危及生命的感染构成非常严重的挑战。KPC-型和ges型碳青霉烯酶是一个特殊的临床问题，因为它们广泛分布于从世界不同地区分离出来的各种革兰氏阴性病原体中。缺乏关于这些酶与碳青霉烯类抗生素相互作用的详细的稳态前动力学研究和结构信息构成了阐明这些有害细菌酶的机制的主要障碍。我们的研究将为未来几代的合理设计提供结构和机理依据。-内酰胺类抗生素和A类碳青霉烯酶抑制剂。我们研究的长期目标是描述A类碳青霉烯酶的详细动力学，阐明这些酶的结构及其与碳青霉烯类抗生素的相互作用。本申请的目标是通过追求三个特定目标来进行A类碳青霉烯酶的详细研究：1)进行临床重要的A类碳青霉烯酶的结构和动力学研究；2)开展新型A类碳青霉烯酶的研究；3)阐明A -内酰胺酶中碳青霉烯酶活性的进化途径。为了阐明这些临床上重要的抗生素耐药酶的机制方面，我们将利用多学科方法，包括分子生物学，蛋白质化学，详细的酶学，质谱和天然酶及其与四种临床使用的碳青霉烯类抗生素复合物的x射线晶体学。阐明最终导致A类获得碳青霉烯酶活性的结构和动力学机制-内酰胺酶将极大地有助于我们了解这些临床重要酶的进化潜力，并将为碳青霉烯类抗生素的未来应用提供重要指导，碳青霉烯类抗生素是治疗危及生命的感染的最后手段。

DESCRIPTION (provided by applicant): Class A carbapenemases in combination with other resistance mechanisms are capable of producing resistance to virtually all available antibiotics and pose a very serious challenge for the successful treatment of life-threatening infections. The KPC- and GES-type carbapenemases are of a special clinical concern as they are widely distributed in various Gram-negative pathogens, isolated from different parts of the world. Lack of a detailed pre-steady-state kinetic studies and structural information regarding interaction of these enzymes with carbapenem antibiotics constitutes the major impediment for elucidation of mechanism(s) of these deleterious bacterial enzymes. Our studies would provide structural and mechanistic basis for rational design of the future generations of ?-lactam antibiotics and inhibitors of class A carbapenemases. The long-term goal of our studies is to delineate detailed kinetics of class A carbapenemases and elucidate structures of these enzymes and their interactions with carbapenem antibiotics. The objectives in this application is to conduct detailed studies of class A carbapenemases by pursuing three Specific Aims: 1) Perform structural and kinetic studies of clinically important class A carbapenemases; 2) Perform studies of novel class A carbapenemases; and 3) Elucidate pathways for evolution of carbapenemase activity in class A ?-lactamases. To elucidate the mechanistic aspects of these clinically important antibiotic-resistance enzymes, we will utilize a multidisciplinary approach that includes molecular biology, protein chemistry, detailed enzymology, mass spectrometry, and X-ray crystallography of the native enzymes and their complexes with four clinically used carbapenem antibiotics. Elucidation of structural and kinetic mechanisms that ultimately resulted in acquisition of carbapenemase activity by class A ?-lactamases would greatly contribute to our understanding of the evolutionary potential of these clinically important enzymes and would provide an important guidance for the future utility of carbapenems, antibiotics of the last resort for treatment of life-threatening infections. PUBLIC HEALTH RELEVANCE: The proposed research is relevant to public health because it elucidates the biomedical process that leads to obsolescence of antibiotics, life-saving drugs that are needed by humanity. Elucidation of the catalytic mechanisms and structures of class A carbapenemases has the potential to result in development of the next generations of ?-lactam antibiotics and inhibitors of these enzymes.