Department of Pharmacology and Chemical Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
Verna Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
Nat Commun. 2018 Oct 30;9(1):4524. doi: 10.1038/s41467-018-06839-1.
New Delhi metallo-β-lactamase-1 exhibits a broad substrate profile for hydrolysis of the penicillin, cephalosporin and 'last resort' carbapenems, and thus confers bacterial resistance to nearly all β-lactam antibiotics. Here we address whether the high catalytic efficiency for hydrolysis of these diverse substrates is reflected by similar sequence and structural requirements for catalysis, i.e., whether the same catalytic machinery is used to achieve hydrolysis of each class. Deep sequencing of randomized single codon mutation libraries that were selected for resistance to representative antibiotics reveal stringent sequence requirements for carbapenem versus penicillin or cephalosporin hydrolysis. Further, the residue positions required for hydrolysis of penicillins and cephalosporins are a subset of those required for carbapenem hydrolysis. Thus, while a common core of residues is used for catalysis of all substrates, carbapenem hydrolysis requires an additional set of residues to achieve catalytic efficiency comparable to that for penicillins and cephalosporins.
新德里金属β-内酰胺酶-1 对青霉素、头孢菌素和“最后手段”碳青霉烯类抗生素的水解具有广泛的底物谱，因此使细菌对几乎所有β-内酰胺类抗生素产生耐药性。在这里，我们研究了对这些不同底物的高催化水解效率是否反映了催化的类似序列和结构要求，即是否使用相同的催化机制来实现每一类的水解。针对代表抗生素的抗性进行随机单密码子突变文库的深度测序表明，碳青霉烯类药物与青霉素或头孢菌素水解的序列要求非常严格。此外，青霉素和头孢菌素水解所需的残基位置是碳青霉烯类水解所需残基位置的子集。因此，虽然所有底物的催化都使用了共同的核心残基，但碳青霉烯类水解需要一组额外的残基来实现与青霉素和头孢菌素相当的催化效率。
