Evolution of DNA binding motifs and operators.
A gene regulatory protein with helix-turn-helix (HTH) DNA-binding motif, GalS contains a functional operator within the DNA sequences encoding the HTH region (Nature 369 (1994) 314). We searched for operator-like sequences within the DNA sequences encoding the DNA binding motifs of other regulatory proteins. Five such proteins, DeoR, CytR, LRP, LuxR and PurR, were found to have actual operator or operator-like sequences in the DNA sequences encoding the DNA-binding motif. Except DeoR, all of them including GalS, are known to be auto-regulated. Auto-regulation in case of DeoR has not been investigated. Seven other proteins containing a HTH motif, do not have operator-like sequences in the DNA sequences encoding the HTH motif; none of them, except MerR, are known to be auto-regulated. The DNA binding proteins may have evolved from a common ancestor containing a DNA binding site within its gene segment that encodes the DNA-binding motif to facilitate auto-regulation. We have discussed current evidence for monophyletic or polyphyletic origin of such sequences.
Roy
Siddhartha
S
Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Building 37, Room 5138, 37 Convent Drive MSC 4264, Bethesda, MD 20892-4264, USA.
Sahu
Ashutosh
A
Adhya
Sankar
S
D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics*; D029968:Escherichia coli Proteins; D019143:Evolution, Molecular; D019077:Helix-Turn-Helix Motifs / Q000235:genetics*; D008969:Molecular Sequence Data; D012097:Repressor Proteins / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D015534:Trans-Activators / Q000235:genetics
D001426:Bacterial Proteins; C048425:CytR protein, E coli; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C050993:Galactose repressor proteins; D012097:Repressor Proteins; D015534:Trans-Activators; C064778:LuxR autoinducer binding proteins