A cognate anti-sigma factor for alternative sigma factor SigF. Alternative sigma factors are held in an inactive form by an anti-sigma factor. Binds ATP and GTP, may hydrolyze both. Homodimer (Probable). Interacts with cognate RNA polymerase sigma factor SigF with a possible 2:1 RbsW:SigF stoichiometry; this inhibits the interaction of SigF with the RNA polymerase catalytic core. Interacts with anti-sigma-F factor antagonist RsfA with a possible 2:1 RbsW:RsfA stoichiometry; this blocks binding to SigF, thus indirectly activating transcription. Interacts with GTPase Obg (PubMed:21352546). 9-fold induced by starvation. The cytosolic domain interacts with sigma factor SigF. A double rsbW-sigF disruption shows no effect in the presence or absence of rifampicin. Belongs to the anti-sigma-factor family. Truncated N-terminus.