Site-directed mutagenesis of the response regulator DmsR for the dmsCBA operon expression in Rhodobacter sphaeroides f. sp. denitrificans: an essential residue of proline-130 in the linker

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• 作者：Yamamoto ; Isamu ; Takamatsu ; Keiko ; Ohshima ; Yoshinori ; Ujiiye ; Takeshi ; Satoh ; Toshio
• 关键词：DmsR ; Response regulator ; Dimethyl sulfoxide reduction ; Proline residue ; Linker ; Rhodobacter sphaeroides f. sp. denitrificans
• 刊名：Biochimica et Biophysica Acta (BBA)/Gene Structure and Expression
• 出版年：1999
• 出版时间：October 6, 1999
• 年：1999
• 卷：1447
• 期：1
• 页码：57-63
• 全文大小：282 K

文摘

DmsR protein is a member of the OmpR response regulator subfamily that activates the transcription of the dmsCBA operon in Rhodobacter sphaeroides f. sp. denitrificans. By site-directed mutagenesis some functional amino acid residues were investigated in DmsR, which consists of the N-terminal regulatory and the C-terminal DNA-binding domains and the linker connecting the two domains. The substitution of P130S in the linker caused decreases of both DNA-binding and transcriptional activator activities. Introducing additional substitutions of R129P or D131P to the DmsR-P130S derivative recovered both activities, demonstrating necessity of proline residue at one of the positions 129–131 in the linker. Substitutions of D12A, D55A, and K104M, at residues conserved in the phosphorylation region, caused no production of DMSO reductase, but retained DNA-binding ability, suggesting that unphosphorylated DmsR also has high affinity to its target nucleotide sequence of DNA. Substitutions in the C-terminal domain suggested the presence of a winged helix-turn-helix structure observed in the DNA-binding domain of the Escherichia coli OmpR.