Regulation of the tryptophan biosynthetic genes in Bacillus halodurans: common elements but different strategies than those used by Bacillus subtilis.
In Bacillus subtilis, an RNA binding protein called TRAP regulates both transcription and translation of the tryptophan biosynthetic genes. Bacillus halodurans is an alkaliphilic Bacillus species that grows at high pHs. Previous studies of this bacterium have focused on mechanisms of adaptation for growth in alkaline environments. We have characterized the regulation of the tryptophan biosynthetic genes in B. halodurans and compared it to that in B. subtilis. B. halodurans encodes a TRAP protein with 71% sequence identity to the B. subtilis protein. Expression of anthranilate synthetase, the first enzyme in the pathway to tryptophan, is regulated significantly less in B. halodurans than in B. subtilis. Examination of the control of the B. halodurans trpEDCFBA operon both in vivo and in vitro shows that only transcription is regulated, whereas in B. subtilis both transcription of the operon and translation of trpE are controlled. The attenuation mechanism that controls transcription in B. halodurans is similar to that in B. subtilis, but there are some differences in the predicted RNA secondary structures in the B. halodurans trp leader region, including the presence of a potential anti-antiterminator structure. Translation of trpG, which is within the folate operon in both bacilli, is regulated similarly in the two species.
Szigeti
Reka
R
Department of Biological Sciences, State University of New York, Buffalo, New York 14260, USA.
Milescu
Mirela
M
Gollnick
Paul
P
D000595:Amino Acid Sequence; D000878:Anthranilate Synthase; D001407:Bacillus / Q000235:genetics* / Q000378:metabolism; D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology; D001483:Base Sequence; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D019884:Nitrogenous Group Transferases / Q000235:genetics; D009876:Operon; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D012313:RNA / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology; D014158:Transcription, Genetic; D014364:Tryptophan / Q000096:biosynthesis*
D001426:Bacterial Proteins; C079092:MtrB protein, Bacteria; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D012313:RNA; D014364:Tryptophan; D019884:Nitrogenous Group Transferases; D000878:Anthranilate Synthase; C020655:anthranilate synthase, glutamine amidotransferase subunit