文献类型：期刊文献

英文题名：Opposite motion of the Central Helices of efflux pump KmrA is important for its export efficiency

作者：Li, Ying[1];Wen, Honglin[2];Ge, Xizhen[1]

第一作者：李映

通讯作者：Ge, XZ[1]

机构：[1]Beijing Union Univ, Coll Biochem Engn, Beijing 100023, Peoples R China;[2]Capital Med Univ, Beijing Hosp Tradit Chinese Med, Beijing 100010, Peoples R China

第一机构：北京联合大学生物化学工程学院

通讯机构：[1]corresponding author), Beijing Union Univ, Coll Biochem Engn, Beijing 100023, Peoples R China.|[1141726]北京联合大学生物化学工程学院;[11417]北京联合大学;

年份：2022

卷号：167

外文期刊名：MICROBIAL PATHOGENESIS

收录：;Scopus(收录号：2-s2.0-85129727693);WOS:【SCI-EXPANDED(收录号:WOS:000829952700009)】；

基金：This work was financially supported by Project of Beijing Municipal Commission of Education (KZ201911417049); Beijing Municipal Education Commission Technology Plan (KM202011417006).

语种：英文

外文关键词：Efflux pump; Major facilitator superfamily; Opposite motion; Antibiotic resistance

摘要：Efflux pump of Major Facilitator Superfamily (MFS) is widely distributed in bacteria, while its role in regulating antibiotic resistance of nosocomial pathogen Klebsiella pneumoniae remains unclear. Herein we analyzed the effect of amino acid substitution of MFS efflux pump KmrA on its export efficiency via molecular biology and molecular dynamics (MD). After searching across the 804 sequenced K. pneumoniae isolates, we identified four major variants of KmrA, while one of them KmrA-A was demonstrated an inactive one in MIC and ethidium bromide efflux assays. Subsequently, MD simulations of KmrA and its variants were conducted and the opposite motion of the central helices were observed for the active variants, while it was not found for KmrA-A. To further identify the importance of the opposite motion to the conformational transition, we calculated their differences in volume of binding pocket, salt bridge and hydrophilic interaction with water based on the rocker-switch model. Our results indicated that the opposite motion of KmrA conferred a larger binding pocket and stronger hydrogen bond with water at inward-facing conformation. An unusual substitution 5374A of KmrA-A disrupted the normal motion of central helices by enhancing hydrophobic interactions between them, resulting into the altered positions and strengths of salt bridge, which was deduced to affect the conformational transition. Overall our data provided detailed information on the regular of KmrA's moving trajectory, demonstrating the importance of opposite motion of central helices to KmrA's export efficiency.