Sequence and domain relationships of ntrC and nifA from Klebsiella pneumoniae: homologies to other regulatory proteins.

Abstract

We have determined the nucleotide sequences of two genes from Klebsiella pneumoniae, nifA, the nif‐specific activator of transcription and ntrC, the bifunctional regulatory protein involved in ‘nitrogen control’. These sequences differ significantly from those previously published. In particular, nifA extends 40 codons beyond the stop codon reported earlier. This extension encodes a putative DNA‐binding domain strongly homologous to the Rhizobium meliloti nifA protein and to some extent to the ntrC protein. In all three proteins this domain is linked by a segment of variable length to a strongly conserved central domain of 240 residues. A short segment having the properties of an interdomain linker joins the central region to an N‐terminal domain, which is weakly related in the case of the two nifA proteins. This homology is not shared by the N‐terminal domain of ntrC, which is clearly but unexpectedly related to the N‐terminal domains of a diverse set of procaryotic pleiotropic control proteins, including ompR, dye and nusA from Escherichia coli and spoOA and spoOF from Bacillus subtilis.

Sequence and structural organization of a nifA-like gene and part of a nifB-like gene of Herbaspirillum seropedicae strain Z78

“…seropedicae NifA-like protein deduced from the nucleotide sequence was compared to the inferred amino acid sequences of NifA proteins from K . pneurnoniae (Buikema et al, 1985;Drummond et al, 1986), R. rneliloti (Buikema et al, 1985), R. legurninosarurn (Gronger et al, 1987) and Azorhizobium caulinodans (Nees et al, 1988) (Fig. 4).…”

“…The NifA amino acid sequences inferred from the determined nucleic acid sequences share a high degree of homology in domains D and E, as defined by Drummond et al (1986). Domain D, the central domain, appears to contain sequences homologous to ATP-binding proteins (Walker et al, 1982).…”

“…Domain D, the central domain, appears to contain sequences homologous to ATP-binding proteins (Walker et al, 1982). Domain E, located in the C-terminal region, contains a helix-turn-helix motif characteristic of DNA-binding proteins; NifA also shares high homology with NtrC in domains D and E (Drummond et al, 1986).…”

A conserved region in the σ54‐dependent activator DctD is involved in both binding to RNA polymerase and coupling ATP hydrolysis to activation

“…In the designations to the left of the amino acid sequences, the first three letters indicate the organism and the last four letters indicate the acronym for the activator. The organisms and activators are: R. meliloti (Rme) DctD (Jiang et al, 1989); S. typhimurium (Sty) NtrC (Flashner et al, 1995); Agrobacterium tumefaciens (Atu) NtrC (Wardhan et al, 1989); R. capsulatus (Rca) NifA (Masepohl et al, 1988); R. capsulatus NtrC (Jones and Haselkorn, 1989); Klebsiella pneumoniae (Kpn) NifA (Drummond et al, 1986); E. coli (Eco) FhlA (Maupin and Shanmugam, 1990); E. coli HydG (Stoker et al, 1989); E. coli TyrR (Cornish et al, 1986); Pseudomonas aeruginosa (Pae) PilR (Ishimoto and Lory, 1992); P. aeruginosa AlgB (Wozniak and Ohman, 1991); Pseudomonas putida (Ppu) XylR (Inouye et al, 1988); P. putida DehR (Topping et al, 1995); Pseudomonas sp. strain CF600 (Psp) DmpR (Shingler et al, 1993); Caulobacter crescentus (Ccr) FlbD (Ramakrishnan and Newton, 1990); Alcaligenes eutrophus (Aeu) HoxA (Eberz and Friedrich, 1991); A .…”

Families of bacterial signal‐transducing proteins

“…A third family of the receiver group consists of the NtrC proteins of Kiebsieiia pneumoniae (Drummond ef at.. 1986). S. typhimurium (Hirschman et al, 1985).…”