RRC ID |
34516
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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.
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タイトル |
Diversities and similarities in pH dependency among bacterial NhaB-like Na+/H+ antiporters.
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ジャーナル |
Microbiology (Reading)
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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.
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巻・号 |
159(Pt 10)
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ページ |
2191-2199
|
公開日 |
2013-10-1
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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
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WOS 分野
|
MICROBIOLOGY
|
リソース情報 |
一般微生物 |
JCM10173 |