Abstract
Cyanobacterial ManR is a member of the OmpR family of response regulator that regulates the expression of themntABC andmntH in response to Mn2+ signals. Single-alanine substitutions of I204, L207 and R208 residues of the ManR, which constituted the DNA recognition helix, were obtained by the overlap extension method of PCR. EMSA was used to detect the complexes of the proteins of ManR mutants I204A, L207A, R208A, and the DNA fragment of promoter region of themntH gene fromAnabaena sp. PCC 7120. Results showed the formation of the complexes of the proteins of ManR mutants and DNA could not be detected, indicating that the mutagenesis of the residues I204, L207 and R208 in the ManR HTH domain could lead to the elimination of DNA binding activity of the ManR. Homologous analysis showed that residues I204, L207 and R208 of the ManR are also conservative in the αhelix 3 region of effector domain of other proteins of OmpR/PhoB subfamily, indicating that they are essential residues for DNA binding activity. No significant alteration between wild type and mutant proteins was detected by Far-UV CD spectra at the secondary structure level.
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Huang, W., Wu, Q., Li, M. et al. Essential residues for DNA binding activity of ManR fromAnabaena sp. PCC 7120. Ann. Microbiol. 56, 53–56 (2006). https://doi.org/10.1007/BF03174970
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DOI: https://doi.org/10.1007/BF03174970