TY - JOUR
T1 - Mutational analysis of the PapB transcriptional regulator in Escherichia coli
T2 - Regions important for DNA binding and oligomerization
AU - Xia, Yan
AU - Uhlin, Bernt Eric
PY - 1999/7/9
Y1 - 1999/7/9
N2 - PapB is a transcriptional regulator in the control of pap operon expression in Escherichia coli. There are PapB homologous proteins encoded by many fimbrial gene systems that are involved in the regulation of fimbriae- adhesin production, and previous studies suggested that PapB binds DNA through minor groove contact. Both deletion and alanine-scanning mutagenesis were used to identify functionally important regions of the PapB protein. Mutations altering Arg61 or Cys65 caused deficiency in DNA binding, indicating that these residues are critical for PapB binding to DNA. Alanine substitutions at positions 35-36, 53-56, and 74-76 resulted in mutants that were impaired in oligomerization. All these amino acid residues are conserved among the PapB homologous proteins, suggesting their importance in the whole family of regulatory proteins. The transcriptional efficiency of all the mutants was clearly reduced as compared with that of wild-type PapB. Taken together, we have localized regions in the PapB protein that are involved in DNA binding and oligomerization, and our results show that both functions are required for its activity as a transcriptional regulator.
AB - PapB is a transcriptional regulator in the control of pap operon expression in Escherichia coli. There are PapB homologous proteins encoded by many fimbrial gene systems that are involved in the regulation of fimbriae- adhesin production, and previous studies suggested that PapB binds DNA through minor groove contact. Both deletion and alanine-scanning mutagenesis were used to identify functionally important regions of the PapB protein. Mutations altering Arg61 or Cys65 caused deficiency in DNA binding, indicating that these residues are critical for PapB binding to DNA. Alanine substitutions at positions 35-36, 53-56, and 74-76 resulted in mutants that were impaired in oligomerization. All these amino acid residues are conserved among the PapB homologous proteins, suggesting their importance in the whole family of regulatory proteins. The transcriptional efficiency of all the mutants was clearly reduced as compared with that of wild-type PapB. Taken together, we have localized regions in the PapB protein that are involved in DNA binding and oligomerization, and our results show that both functions are required for its activity as a transcriptional regulator.
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U2 - 10.1074/jbc.274.28.19723
DO - 10.1074/jbc.274.28.19723
M3 - Article
C2 - 10391913
AN - SCOPUS:0033538488
SN - 0021-9258
VL - 274
SP - 19723
EP - 19730
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 28
ER -