title: Domain architecture and structure of the bacterial cell division protein DivIB.
abstract: Bacterial cytokinesis requires the coordinated assembly of a complex of proteins, collectively known as the divisome, at the incipient division site. DivIB/FtsQ is a conserved component of the divisome in bacteria with cell walls, suggesting that it plays a role in synthesis and/or remodeling of septal peptidoglycan. We demonstrate that the extracytoplasmic region of DivIB comprises three discrete domains that we designate alpha, beta, and gamma from the N to C terminus. The alpha-domain is proximal to the cytoplasmic membrane and coincident with the polypeptide transport-associated domain that was proposed previously to function as a molecular chaperone. The beta-domain has a unique 3D fold, with no eukaryotic counterpart, and we show that it interconverts between two discrete conformations via cis-trans isomerization of a Tyr-Pro peptide bond. We propose that this isomerization might modulate protein-protein interactions of the flanking alpha- and gamma-domains. The C-terminal gamma-domain is unstructured in the absence of other divisomal proteins, but we show that it is critical for DivIB function.
authors.affiliation: Department of Molecular, Microbial, and Structural Biology and Partnership for Excellence in Structural Biology, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-3305, USA.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Robson
authors.forename: Glenn F
authors.initials: GF
authors.lastname: King
mesh_terms: D000595:Amino Acid Sequence; D001406:Bacillaceae / Q000737:chemistry / Q000235:genetics; D001412:Bacillus subtilis / Q000737:chemistry / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D002455:Cell Division; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; C085861:DivIB protein, Bacillus subtilis; D029968:Escherichia coli Proteins; C068023:FtsQ protein, E coli; D008565:Membrane Proteins; D011994:Recombinant Proteins