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Publication Abstract from PubMed

Bacillus subtilis DegQ is a 46-amino-acid regulatory protein involved in the DegS-DegU two-component system. DegQ promotes the phosphorylation of DegU by DegS, switching the function of DegU from competence to the induction of poly-gamma-glutamate production. To elucidate its structural role, we determined the crystal structures of wild-type DegQ and its mutant DegQS25L. Each DegQ monomer folds into a single alpha-helix, and four monomers assemble into a tetramer characterized by a four-helix coiled-coil structure. Within the tetramer, two adjacent helices are oriented in the same direction, while the other two are oriented oppositely, forming a pseudo-twofold symmetric arrangement. The mutant form displays disrupted symmetry due to altered helix packing, which is caused by shifts in the coiled-coil heptad register induced by the mutation. Structural predictions using AlphaFold3 suggest that DegQ likely binds to the N-terminal helix bundle of DegS, either as a dimer or as individual monomers. These findings provide structural insight into DegQ oligomerization and its potential role in modulating DegS autophosphorylation and DegU binding.

Tetrameric structure of Bacillus subtilis DegQ and its predicted interaction with the DegS-DegU two-component system.,Fujimoto Z, Kishine N, Saitou K, Kimura K Acta Crystallogr F Struct Biol Commun. 2025 Oct 1. doi: , 10.1107/S2053230X25007903. PMID:40937771^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.