摘要

对广谱β-内酰胺类抗生素具有活性的金属-β-内酰胺酶（MBLs）已成为公众健康的主要威胁，这不仅是因为它们能够快速适应其底物偏好。在该研究中，MBL AIM-1通过引入特定突变逃避抗生素压力的能力通过两种替代方法探测，即活性位点残基的位点饱和诱变（SSM）和体外进化。两种方法均表明，AIM-1中的单个突变可以极大地增强病原体对广谱抗生素的抗性，而不显着损害酶的催化效率。重要的是，进化实验表明相关的氨基酸不一定非常靠近酶的催化中心。这一观察结果是一个有力的证明，MBL具有多种可能性来适应新的选择压力，这种途径无法从晶体结构单独预测。

Metallo-β-lactamases (MBLs) with activity towards a broad-spectrum of β-lactam antibiotics have become a major threat to public health, not least due to their ability to rapidly adapt their substrate preference. In this study, the capability of the MBL AIM-1 to evade antibiotic pressure by introducing specific mutations was probed by two alternative methods, i.e. site-saturation mutagenesis (SSM) of active site residues and in vitro evolution. Both approaches demonstrated that a single mutation in AIM-1 can greatly enhance a pathogen’s resistance towards broad spectrum antibiotics without significantly compromising the catalytic efficiency of the enzyme. Importantly, the evolution experiments demonstrated that relevant amino acids are not necessarily in close proximity to the catalytic centre of the enzyme. This observation is a powerful demonstration that MBLs have a diverse array of possibilities to adapt to new selection pressures, avenues that cannot easily be predicted from a crystal structure alone.

https://www.frontiersin.org/articles/10.3389/fmicb.2017.00812/full