Publication Abstract from PubMed
AbrB is a key transition-state regulator of Bacillus subtilis. Based on the conservation of a betaalphabeta structural unit, we proposed a beta barrel fold for its DNA binding domain, similar to, but topologically distinct from, double-psi beta barrels. However, the NMR structure revealed a novel fold, the "looped-hinge helix." To understand this discrepancy, we undertook a bioinformatics study of AbrB and its homologs; these form a large superfamily, which includes SpoVT, PrlF, MraZ, addiction module antidotes (PemI, MazE), plasmid maintenance proteins (VagC, VapB), and archaeal PhoU homologs. MazE and MraZ form swapped-hairpin beta barrels. We therefore reexamined the fold of AbrB by NMR spectroscopy and found that it also forms a swapped-hairpin barrel. The conservation of the core betaalphabeta element supports a common evolutionary origin for swapped-hairpin and double-psi barrels, which we group into a higher-order class, the cradle-loop barrels, based on the peculiar shape of their ligand binding site.
AbrB-like transcription factors assume a swapped hairpin fold that is evolutionarily related to double-psi beta barrels.,Coles M, Djuranovic S, Soding J, Frickey T, Koretke K, Truffault V, Martin J, Lupas AN Structure. 2005 Jun;13(6):919-28. PMID:15939023[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
