RRC ID 34516
著者 Kiriyama W, Honma K, Hiratsuka T, Takahashi I, Nomizu T, Takashima Y, Ohtsuka M, Takahashi D, Moriyama K, Mori S, Nishiyama S, Fukuhara M, Nakamura T, Shigematsu T, Yamaguchi T.
タイトル Diversities and similarities in pH dependency among bacterial NhaB-like Na+/H+ antiporters.
ジャーナル Microbiology (Reading)
Abstract NhaB-like antiporters were the second described class of Na(+)/H(+) antiporters, identified in bacteria more than 20 years ago. While nhaB-like gene sequences have been found in a number of bacterial genomes, only a few of the NhaB-like antiporters have been functionally characterized to date. Although earlier studies have identified a few pH-sensitive and -insensitive NhaB-like antiporters, the mechanisms that determine their pH responses still remain elusive. In this study, we sought to investigate the diversities and similarities among bacterial NhaB-like antiporters, with particular emphasis on their pH responsiveness. Our phylogenetic analysis of NhaB-like antiporters, combined with pH profile analyses of activities for representative members of several phylogenetic groups, demonstrated that NhaB-like antiporters could be classified into three distinct types according to the degree of their pH dependencies. Interestingly, pH-insensitive NhaB-like antiporters were only found in a limited proportion of enterobacterial species, which constitute a subcluster that appears to have diverged relatively recently among enterobacterial NhaB-like antiporters. Furthermore, kinetic property analyses of NhaB-like antiporters at different pH values revealed that the degree of pH sensitivity of antiport activities was strongly correlated with the magnitude of pH-dependent change in apparent Km values, suggesting that the dramatic pH sensitivities observed for several NhaB-like antiporters might be mainly due to the significant increases of apparent Km at lower pH. These results strongly suggested the possibility that the loss of pH sensitivity of NhaB-like antiporters had occurred relatively recently, probably via accumulation of the mutations that impair pH-dependent change of Km in the course of molecular evolution.
巻・号 159(Pt 10)
ページ 2191-2199
公開日 2013-10-1
DOI 10.1099/mic.0.070656-0
PMID 23938609
MeSH Bacteria / drug effects Bacteria / enzymology* Bacteria / genetics DNA, Bacterial / chemistry DNA, Bacterial / genetics Genetic Variation Hydrogen-Ion Concentration Kinetics Molecular Sequence Data Phylogeny Sequence Analysis, DNA Sodium-Hydrogen Exchangers / classification Sodium-Hydrogen Exchangers / drug effects Sodium-Hydrogen Exchangers / genetics Sodium-Hydrogen Exchangers / metabolism*
IF 2.138
引用数 2
WOS 分野 MICROBIOLOGY
リソース情報
一般微生物 JCM10173