Life Sciences Institute, 210 Washtenaw Ave, University of Michigan, Ann Arbor, MI 48109-2216, USA.
Biochimie. 2013 Jun;95(6):1319-25. doi: 10.1016/j.biochi.2013.02.011. Epub 2013 Feb 26.
Aminoglycosides (AGs) are broad-spectrum antibiotics whose constant use and presence in growth environments has led bacteria to develop resistance mechanisms to aid in their survival. A common mechanism of resistance to AGs is their chemical modification (nucleotidylation, phosphorylation, or acetylation) by AG-modifying enzymes (AMEs). Through evolution, fusion of two AME-encoding genes has resulted in bifunctional enzymes with broader spectrum of activity. Serratia marcescens, a human enteropathogen, contains such a bifunctional enzyme, ANT(3″)-Ii/AAC(6')-IId. To gain insight into the role, effect, and importance of the union of ANT(3″)-Ii and AAC(6')-IId in this bifunctional enzyme, we separated the two domains and compared their activity to that of the full-length enzyme. We performed a thorough comparison of the substrate and cosubstrate profiles as well as kinetic characterization of the bifunctional ANT(3″)-Ii/AAC(6')-IId and its individually expressed components.
氨基糖苷类（AGs）是一种广谱抗生素，由于其在生长环境中的持续使用和存在，导致细菌产生了抵抗机制以帮助其生存。一种常见的抗 AG 机制是通过 AG 修饰酶（AMEs）对其进行化学修饰（核苷酸化、磷酸化或乙酰化）。通过进化，两个 AME 编码基因的融合产生了具有更广泛活性谱的双功能酶。粘质沙雷氏菌是一种人类肠道病原体，含有这样一种双功能酶，即 ANT(3″)-Ii/AAC(6')-IId。为了深入了解这种双功能酶中 ANT(3″)-Ii 和 AAC(6')-IId 的结合在其中的作用、影响和重要性，我们分离了这两个结构域，并将它们的活性与全长酶进行了比较。我们对双功能 ANT(3″)-Ii/AAC(6')-IId 及其单独表达的成分进行了彻底的底物和共底物谱比较以及动力学特征分析。
