The promoter of the operon encoding the F0F1 ATPase of Streptococcus pneumoniae is inducible by pH

Citation
Aj. Martin-galiano et al., The promoter of the operon encoding the F0F1 ATPase of Streptococcus pneumoniae is inducible by pH, MOL MICROB, 41(6), 2001, pp. 1327-1338
Citations number
46
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
MOLECULAR MICROBIOLOGY
ISSN journal
0950-382X → ACNP
Volume
41
Issue
6
Year of publication
2001
Pages
1327 - 1338
Database
ISI
SICI code
0950-382X(200109)41:6<1327:TPOTOE>2.0.ZU;2-E
Abstract
The genes encoding the subunits of the F0F1 membrane ATPase of Streptococcu s pneumoniae were cloned and sequenced. The eight genes, transcribed to one mRNA, are organized in an operon encoding the c, a, b, delta, alpha, gamma , beta and epsilon subunits of 66, 238,165,178, 501, 292, 471 and 139 amino acid residues, respectively, that were expressed in an Escherichia coli sy stem. To investigate the role of the ATPase in the regulation of the intrac ellular pH, the expression of the operon between pH 5.7 and 7.5 was studied . An increase in both the ATPase activity and the amount of the alpha and b eta F-1 subunits as shown by Western blot analysis was observed as the pH d ecreased. These increases were accompanied by an increase in the atp-specif ic mRNA, as shown by Northern blot and slot-blot analysis. Primer extension experiments and transcriptional fusions between the atp promoter and the r eporter cat gene demonstrated that this pH-dependent increase in the mRNA w as regulated at the level of initiation of transcription. Transcription of the operon occurs from a promoter with a consensus -35 box (TTGACA) and a - 10 box (TACACT) that differs from the consensus (TATAAT). A point mutation at the -10 box of the promoter (change to TGCACT) avoided this increase, su ggesting a role for this sequence in the pH-inducible regulation.