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BIBTEX RIS

The helix-turn-helix motif of sigma 54 is involved in recognition of the -13 promoter region

1992; American Society for Microbiology; Volume: 174; Issue: 22 Linguagem: Inglês

10.1128/jb.174.22.7221-7226.1992

ISSN

1098-5530

Autores

Mike Merrick, S Chambers,

Tópico(s)

RNA Research and Splicing

Resumo

Residue Arg-383 in the proposed helix-turn-helix motif of the novel RNA polymerase sigma factor sigma 54 has been changed by site-directed mutagenesis to all possible alternative amino acids. Only two mutants, RK383 and RH383, are active in promoting transcription from either the glnAp2 promoter or the nifL promoter. We constructed a set of mutant derivatives of glnAp2 such that each base in the conserved GG and GC doublets at -24 and -12 was changed to all possible alternatives. All 12 mutant glnAp2 promoters showed a marked promoter-down phenotype with wild-type sigma 54, but RK383 suppressed changes of both G to C and G to T at -13. This result suggests that the sigma 54 helix-turn-helix is involved in recognition of the -13 region of sigma 54-dependent promoters.

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