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. 1999 Aug;181(15):4628–4638. doi: 10.1128/jb.181.15.4628-4638.1999

TABLE 4.

Motifs in the central domain of NtrCa

Binding Hydrolysis Hydrolysis Hydrolysis Binding
G173 S207/E208 D239 R294 G355/R358
Walker A, binds β phosphate Switch I effector Walker B/switch II, coordinates Mg2+ Catalytic residue? Binds nucleotide base
GESGTG173KE ES207ELFGHEKGAFTGA GGTLFLD239EIG FR294EDLfhRLNV WPG355NVR358qLEN
a

For the central domains of NtrC proteins of S. typhimurium, E. coli, K. pneumoniae, Proteus vulgaris, Rhizobium meliloti, Bradyrhizobium parasponiae, and Agrobacterium tumefaciens (15, 43). The motifs listed are also referred to as conserved regions 1, 3, 4, 6, and 7, respectively, among activators of ς54-holoenzyme (36, 43). Conserved region 6 begins with residue 275 of NtrC and extends through residue 312. For cases in which fewer than four of the five NtrC sequences are identical, the residue is that for the protein from S. typhimurium and is in lowercase. The numbers indicate positions at which amino acid substitutions in the NtrC protein of S. typhimurium were studied in this work.