The transcriptional regulator gene phrR in Sinorhizobium meliloti WSM419 is regulated by low pH and other stresses.
The phrR gene in Sinorhizobium meliloti (previously known as Rhizobium meliloti) WSM419, directly downstream from actA, is induced by low pH or certain stresses (e.g. high concentrations of Zn2+, Cu2+, H2O2 or ethanol), but not in stationary phase or by other stresses (e.g. phosphate limitation, elevated temperature, high concentrations of sucrose or iron). A DNA fragment containing the wild-type phrR gene could not be cloned and inverse PCR was therefore used to amplify a 3.5 kb BamHI fragment containing phrR from the mutant S. meliloti TG2-6 (actA::Tn5). DNA fragments from a BamHI/SalI digest of the amplified product were cloned into pUK21 and sequenced. The phrR open reading frame contiguous to actA appears to code for a 15.2 kDa protein showing significant identity with the proteins encoded by y4wC and y4aM in Rhizobium sp. NGR234. All three proteins resemble transcriptional regulators in containing a DNA-binding helix-turn-helix motif similar to that reported for URF4 in Rhodospirillum rubrum and repressors in coliphage.
Reeve
Wayne G
WG
Tiwari
Ravi P
RP
Wong
Cheryl M
CM
Dilworth
Michael J
MJ
Glenn
Andrew R
AR
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D015964:Gene Expression Regulation, Bacterial; D006863:Hydrogen-Ion Concentration; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D012097:Repressor Proteins / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D016962:Sinorhizobium meliloti / Q000235:genetics*
D001426:Bacterial Proteins; D008565:Membrane Proteins; C118506:PhrR protein, Sinorhizobium meliloti; D012097:Repressor Proteins; C072980:actA protein, Listeria monocytogenes