AUTHOR=Takahashi Tetsuaki , Krulwich Terry A. , Ito Masahiro 

TITLE=A Hydrophobic Small Protein, BpOF4_01690, Is Critical for Alkaliphily of Alkaliphilic Bacillus pseudofirmus OF4

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.01994

DOI=10.3389/fmicb.2018.01994

ISSN=1664-302X

ABSTRACT=<p>A monocistronic small protein, BpOF4_01690, was annotated in alkaliphilic <italic>Bacillus pseudofirmus</italic> OF4. It comprises 59 amino acids and is hydrophobic. Importantly, homologs of this protein were identified only in alkaliphiles. In this study, a mutant with a BpOF4_01690 gene deletion (designated Δ01690) exhibited weaker growth than that of the wild type in both malate-based defined and glucose-based defined media under low-sodium conditions at pH 10.5. Additionally, the enzymatic activity of the respiratory chain of Δ01690 was much lower than that of the wild type. These phenotypes were similar to those of a <italic>ctaD</italic> deletion mutant and an <italic>atpB-F</italic> deletion mutant. Therefore, we hypothesize that BpOF4_01690 plays a critical role in oxidative phosphorylation under highly alkaline conditions.</p>