Open AccessDNA-binding determinants of sigma 54 as deduced from libraries of mutations
Author(s) -
Yanjie Guo,
Jay D. Gralla
Publication year - 1997
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.179.4.1239-1245.1997
Subject(s) - biology , mutagenesis , dna , point mutation , amino acid , function (biology) , mutation , escherichia coli , genetics , binding domain , binding site , sigma , microbiology and biotechnology , biochemistry , gene , physics , quantum mechanics
PCR mutagenesis was used to obtain libraries of mutations in the region between amino acids 300 and 400 in the DNA-binding domain of Escherichia coli sigma 54. Two hundred changes that did not alter function were identified. These were compared with a somewhat smaller number of changes that did alter function. Several important regions were identified. Single point mutations in two of these, near amino acids 363 and 383, destroyed the ability of sigma to bind DNA, as assayed by band shift analysis. A third segment from amino acids 327 to 347 is also a candidate for contributing to DNA binding. Comparison with data in the literature leads to testable proposals for the complex mode of DNA binding that is associated with sigma 54.