|PROSITE documentation PDOC00861 [for PROSITE entry PS50995]|
The marR-type HTH domain is a DNA-binding, winged helix-turn-helix (wHTH) domain of about 135 amino acids present in transcription regulators of the marR/slyA family, involved in the development of antibiotic resistance. This family of transcription regulators is named after Escherichia coli marR, a repressor of genes which activate the multiple antibiotic resistance and oxidative stress regulons, and after slyA from Salmonella typhimurium and E. coli, a transcription regulator that is required for virulence and survival in the macrophage environment. Regulators with the marR-type HTH domain are present in bacteria and archaea and control a variety of biological functions, including resistance to multiple antibiotics, household disinfectants, organic solvents, oxidative stress agents and regulation of the virulence factor synthesis in pathogens of humans and plants. Many of the marR-like regulators respond to aromatic compounds [1,2,3].
The crystal structures of marR, mexR and slyA have been determined and show a winged HTH DNA-binding core flanked by helices involved in dimerization (see <PDB:1LJ9>). The DNA-binding domains are ascribed to the superfamily of winged helix proteins, containing a three (four)-helix (H) bundle and a three-stranded antiparallel β-sheet (B) in the topology: H1-(H1')-H2-B1-H3-H4-B2-B3-H5-H6. Helices 3 and 4 comprise the helix-turn-helix motif and the β-sheet is called the wing. Helix 4 is termed the recognition helix, like in other HTHs where it binds the DNA major groove. The helices 1, 5 and 6 are involved in dimerization, as most marR-like transcription regulators form dimers [3,4,5].
Some proteins known to contain a marR-type HTH domain:
As a signature pattern, we have selected a 34 residue segment showing high conservation within this family. This conserved region from helix 3 to strand 3 is located in the DNA binding domain. We also developed a profile that covers the entire wHTH, including helix 1 and the conserved part of helix 6, and which allows a more sensitive detection.Last update:
April 2006 / Pattern revised.
PROSITE methods (with tools and information) covered by this documentation:
|1||Authors||Alekshun M.N. Levy S.B.|
|Title||The mar regulon: multiple resistance to antibiotics and other toxic chemicals.|
|Source||Trends Microbiol. 7:410-413(1999).|
|2||Authors||Egland P.G. Harwood C.S.|
|Title||BadR, a new MarR family member, regulates anaerobic benzoate degradation by Rhodopseudomonas palustris in concert with AadR, an Fnr family member.|
|Source||J. Bacteriol. 181:2102-2109(1999).|
|3||Authors||Wu R.Y. Zhang R.G. Zagnitko O. Dementieva I. Maltzev N. Watson J.D. Laskowski R. Gornicki P. Joachimiak A.|
|Title||Crystal structure of Enterococcus faecalis SlyA-like transcriptional factor.|
|Source||J. Biol. Chem. 278:20240-20244(2003).|
|4||Authors||Alekshun M.N. Levy S.B. Mealy T.R. Seaton B.A. Head J.F.|
|Title||The crystal structure of MarR, a regulator of multiple antibiotic resistance, at 2.3 A resolution.|
|Source||Nat. Struct. Biol. 8:710-714(2001).|
|5||Authors||Lim D. Poole K. Strynadka N.C.J.|
|Title||Crystal structure of the MexR repressor of the mexRAB-oprM multidrug efflux operon of Pseudomonas aeruginosa.|
|Source||J. Biol. Chem. 277:29253-29259(2002).|