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- ******************************************
- * Sigma-54 interaction domain signatures *
- ******************************************
-
- Some bacterial regulatory proteins activate the expression of genes from
- promoters recognized by core RNA polymerase associated with the alternative
- sigma-54 factor. These have a conserved domain of about 230 residues involved
- in the ATP-dependent [1,2] interaction with sigma-54. This domain has been
- found in the proteins listed below:
-
- - acoR from Alcaligenes eutrophus, an activator of the acetoin catabolism
- operon acoXABC.
- - algB from Pseudomonas aeruginosa, an activator of alginate biosynthetic
- gene algD.
- - dctD from Rhizobium, an activator of dctA, the C4-dicarboxylate transport
- protein.
- - fhlA from Escherichia coli, an activator of the formate dehydrogenase H and
- hydrogenase III structural genes.
- - flbD from Caulobacter crescentus, an activator of flagellar genes.
- - hoxA from Alcaligenes eutrophus, an activator of the hydrogenase operon.
- - hrpS from Pseudomonas syringae, an activator of hprD as well as other hrp
- loci involved in plant pathogenicity.
- - hupR1 from Rhodobacter capsulatus, an activator of the [NiFe] hydrogenase
- genes hupSL.
- - hydG from Escherichia coli and Salmonella typhimurium, an activator of the
- hydrogenase activity.
- - levR from Bacillus subtilis, which regulates the expression of the levanase
- operon (levDEFG and sacC).
- - nifA (as well as anfA and vnfA) from various bacteria, an activator of the
- nif nitrogen-fixing operon.
- - ntrC, from various bacteria, an activator of nitrogen assimilatory genes
- such as that for glutamine synthetase (glnA) or of the nif operon.
- - pgtA from Salmonella typhimurium, the activator of the inducible phospho-
- glycerate transport system.
- - pilR from Pseudomonas aeruginosa, an activator of pilin gene transcription.
- - tyrR from Escherichia coli, involved in the transcriptional regulation of
- aromatic amino-acid biosynthesis and transport.
- - wtsA, from Erwinia stewartii, an activator of plant pathogenicity gene
- wtsB.
- - xylR from Pseudomonas putida, the activator of the tol plasmid xylene
- catabolism operon xylCAB and of xylS.
-
- About half of these proteins (algB, dcdT, flbD, hoxA, hupR1, hydG, ntrC, pgtA
- and pilR) belong to signal transduction two-component systems [3] and possess
- a domain that can be phosphorylated by a sensor-kinase protein in their N-
- terminal section. Almost all of these proteins possess a helix-turn-helix
- DNA-binding domain in their C-terminal section.
-
- The domain which interacts with the sigma-54 factor has an ATPase activity.
- This may be required to promote a conformational change necessary for the
- interaction [4]. The domain contains an atypical ATP-binding motif A (P-loop)
- as well as a form of motif B. The two ATP-binding motifs are located in the N-
- terminal section of the domain; we have developed signature patterns for both
- motifs. Other regions of the domain are also conserved. We have selected one
- of them, located in the C-terminal section, as a third signature pattern.
-
- -Consensus pattern: [LIVMFY](3)-x-G-[DE]-[ST]-G-[ST]-G-K-x(2)-[LIVMFY]
- -Sequences known to belong to this class detected by the pattern: A majority.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Consensus pattern: G-x-[LIVMF]-x(2)-A-[DNEQASH]-[GNEK]-G-[STI]-[LIVMFY](3)-D-
- E-[LIVM]
- -Sequences known to belong to this class detected by the pattern: A majority.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Consensus pattern: [FYW]-P-[GS]-N-[LIVM]-R-[EQ]-L-x-[NHAT]
- -Sequences known to belong to this class detected by the pattern: Almost all
- of these proteins.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Last update: June 1994 / Patterns and text revised.
-
- [ 1] Morrett E., Segovia L.
- J. Bacteriol. 175:6067-6074(1993).
- [ 2] Austin S., Kundrot C., Dixon R.
- Nucleic Acids Res. 19:2281-2287(1991).
- [ 3] Albright L.M., Huala E., Ausubel F.M.
- Annu. Rev. Genet. 23:311-336(1989).
- [ 4] Austin S., Dixon R.
- EMBO J. 11:2219-2228(1992).
-