Structural insights into the redox-switch mechanism of the MarR/DUF24-type regulator HypR.
Nucleic Acids Res
; 40(9): 4178-92, 2012 May.
Article
em En
| MEDLINE
| ID: mdl-22238377
ABSTRACT
Bacillus subtilis encodes redox-sensing MarR-type regulators of the OhrR and DUF24-families that sense organic hydroperoxides, diamide, quinones or aldehydes via thiol-based redox-switches. In this article, we characterize the novel redox-sensing MarR/DUF24-family regulator HypR (YybR) that is activated by disulphide stress caused by diamide and NaOCl in B. subtilis. HypR controls positively a flavin oxidoreductase HypO that confers protection against NaOCl stress. The conserved N-terminal Cys14 residue of HypR has a lower pK(a) of 6.36 and is essential for activation of hypO transcription by disulphide stress. HypR resembles a 2-Cys-type regulator that is activated by Cys14-Cys49' intersubunit disulphide formation. The crystal structures of reduced and oxidized HypR proteins were resolved revealing structural changes of HypR upon oxidation. In reduced HypR a hydrogen-bonding network stabilizes the reactive Cys14 thiolate that is 8-9 Å apart from Cys49'. HypR oxidation breaks these H-bonds, reorients the monomers and moves the major groove recognition α4 and α4' helices â¼4 Å towards each other. This is the first crystal structure of a redox-sensing MarR/DUF24 family protein in bacteria that is activated by NaOCl stress. Since hypochloric acid is released by activated macrophages, related HypR-like regulators could function to protect pathogens against the host immune defense.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Bacillus subtilis
/
Proteínas de Bactérias
/
Regulação Bacteriana da Expressão Gênica
/
Ativação Transcricional
/
Transativadores
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article