| Type: | Conserved_site | Name: | Transcriptional regulator MarR-type, conserved site |
| Description: | 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. The MarR family of transcription regulators is named after Escherichia coliMarR, a repressor of genes which activate the multiple antibiotic resistance and oxidative stress regulons, and after slyA from Salmonella typhimuriumand E. coli, a transcription regulator that is required for virulence and survival in the macrophage environment. Regulators with the MarR-type HTH domain arepresent in bacteria and archaea and control a variety of biological functions, including resistance to multiple antibiotics, household disinfectants, organicsolvents, oxidative stress agents and regulation of the virulence factor synthesis in pathogens of humans and plants. Many of the MarR-like regulatorsrespond to aromatic compounds [, , ].The crystal structures of MarR, MexR and SlyA have been determined and show a winged HTH DNA-binding core flanked by helices involved in dimerisation. 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 beta-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 beta-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 dimerisation, as most MarR-like transcription regulators form dimers [, ].This entry represents a 34 residue conserved site showing high conservation within this family. | Short Name: | Tscrpt_reg_MarR-type_CS |
