5wuq
From Proteopedia
Crystal structure of SigW in complex with its anti-sigma RsiW, a zinc binding form
Structural highlights
Function[SIGW_BACSU] Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released. Extracytoplasmic function (ECF) sigma factors are held in an inactive form by a cognate anti-sigma factor (RsiW for this protein) until released by regulated membrane proteolysis. Sigma-W controls genes involved in transport processes and detoxification.[1] [2] [RSIW_BACSU] Is the anti-sigma factor for extracytoplasmic function (ECF) sigma factor SigW. Holds SigW, its cognate ECF sigma factor, in an inactive form until released by regulated intramembrane proteolysis.[3] [4] Publication Abstract from PubMedBacillus subtilis SigW is localized to the cell membrane and is inactivated by the tight interaction with anti-sigma RsiW under normal growth conditions. Whereas SigW is discharged from RsiW binding and thus initiates the transcription of its regulon under diverse stress conditions such as antibiotics and alkaline shock. The release and activation of SigW in response to extracytoplasmic signals is induced by the regulated intramembrane proteolysis of RsiW. As a ZAS (Zinc-containing anti-sigma) family protein, RsiW has a CHCC zinc binding motif, which implies that its anti-sigma activity may be regulated by the state of zinc coordination in addition to the proteolytic cleavage of RsiW. To understand the regulation mode of SigW activity by RsiW, we determined the crystal structures of SigW in complex with the cytoplasmic domain of RsiW, and compared the conformation of the CHCC motif in the reduced/zinc binding and the oxidized states. The structures revealed that RsiW inhibits the promoter binding of SigW by interacting with the surface groove of SigW. The interaction between SigW and RsiW is not disrupted by the oxidation of the CHCC motif in RsiW, suggesting that SigW activity might not be regulated by the zinc coordination states of the CHCC motif. Structural insights into the regulation of Bacillus subtilis SigW activity by anti-sigma RsiW.,Devkota SR, Kwon E, Ha SC, Chang HW, Kim DY PLoS One. 2017 Mar 20;12(3):e0174284. doi: 10.1371/journal.pone.0174284., eCollection 2017. PMID:28319136[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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