Competence repression under oxygen limitation through the two-component MicAB signal-transducing System in Streptococcus pneumoniae and Involvement of the PAS Domain of MicB

ECHENIQUE J; TROMBE MC

AMER SOC MICROBIOLOGY

Año: 2001 vol. 183 p. 4599 - 4599

b> In Streptococcus pneumoniae, a fermentative aerotolerant and catalase-deficient human pathogen, oxidases with molecular oxygen as substrate are important for virulence and for competence. The signal-transducing two-component systems CiaRH and ComDE mediate the response to oxygen, culminating in competence. In this work we show that the two-component MicAB system, whose MicB kinase carries a PAS domain, is also involved in competence repression under oxygen limitation. Autophosphorylation of recombinant MicB and phosphotransfer to recombinant MicA have been demonstrated. Mutational analysis and in vitro assays showed that the C-terminal part of the protein and residue L100 in the N-terminal cap of its PAS doma