Structural highlights
Function
[SP2AB_BACST] Binds to sigma F and blocks its ability to form an RNA polymerase holoenzyme (E-sigma F). Phosphorylates SpoIIAA on a serine residue. This phosphorylation may enable SpoIIAA to act as an anti-anti-sigma factor that counteracts SpoIIAB and thus releases sigma F from inhibition (By similarity). [SP2AA_BACST] In the phosphorylated form it could act as an anti-anti-sigma factor that counteracts SpoIIAB and thus releases sigma f from inhibition (By similarity).
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Cell type-specific transcription during Bacillus sporulation is established by sigma(F), the activity of which is controlled by a regulatory circuit involving the anti-sigma factor and serine kinase SpoIIAB, and the anti-anti-sigma SpoIIAA. When ATP is present in the nucleotide-binding site of SpoIIAB, SpoIIAA is phosphorylated, followed by dissociation. The nucleotide-binding site of SpoIIAB is left bound to ADP. SpoIIAB(ADP) can bind an unphosphorylated molecule of SpoIIAA as a stable binding partner. Thus, in this circuit, SpoIIAA plays a dual role as a substrate of the SpoIIAB kinase activity, as well as a tight binding inhibitor. Crystal structures of both the pre-phosphorylation complex and the inhibitory complex, SpoIIAB(ATP) and SpoIIAB(ADP) bound to SpoIIAA, respectively, have been determined. The structural differences between the two forms are subtle and confined to interactions with the phosphoryl groups of the nucleotides. The structures reveal details of the SpoIIAA:SpoIIAB interactions and how phosphorylated SpoIIAA dissociates from SpoIIAB(ADP). Finally, the results confirm and expand upon the docking model for SpoIIAA function as an anti-anti-sigma in releasing sigma(F) from SpoIIAB.
Crystal structures of the ADP and ATP bound forms of the Bacillus anti-sigma factor SpoIIAB in complex with the anti-anti-sigma SpoIIAA.,Masuda S, Murakami KS, Wang S, Anders Olson C, Donigian J, Leon F, Darst SA, Campbell EA J Mol Biol. 2004 Jul 23;340(5):941-56. PMID:15236958[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Masuda S, Murakami KS, Wang S, Anders Olson C, Donigian J, Leon F, Darst SA, Campbell EA. Crystal structures of the ADP and ATP bound forms of the Bacillus anti-sigma factor SpoIIAB in complex with the anti-anti-sigma SpoIIAA. J Mol Biol. 2004 Jul 23;340(5):941-56. PMID:15236958 doi:10.1016/j.jmb.2004.05.040
