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

AUTOR(ES)

Merrick, M

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.

Documentos Relacionados

• In vitro roles of invariant helix–turn–helix motif residue R383 in σ54 (σN)
• The helix–turn–helix motif of bacterial insertion sequence IS911 transposase is required for DNA binding
• Lac repressor with the helix-turn-helix motif of lambda cro binds to lac operator.
• Amino acids determining operator binding specificity in the helix-turn-helix motif of Tn10 Tet repressor.
• Solution structure of the ETS domain from murine Ets-1: a winged helix-turn-helix DNA binding motif.