title: Novel hexamerization motif is discovered in a conserved cytoplasmic protein from Salmonella typhimurium.
abstract: The cytoplasmic protein Stm3548 of unknown function obtained from a strain of Salmonella typhimurium was determined by X-ray crystallography at a resolution of 2.25 A. The asymmetric unit contains a hexamer of structurally identical monomers. The monomer is a globular domain with a long beta-hairpin protrusion that distinguishes this structure. This beta-hairpin occupies a central position in the hexamer, and its residues participate in the majority of interactions between subunits of the hexamer. We suggest that the structure of Stm3548 presents a new hexamerization motif. Because the residues participating in interdomain interactions are highly conserved among close members of protein family DUF1355 and buried solvent accessible area for the hexamer is significant, the hexamer is most likely conserved as well. A light scattering experiment confirmed the presence of hexamer in solution.
authors.affiliation: Midwest Center for Structural Genomics and Structural Biology Center, Biosciences, Argonne National Laboratory, Argonne, IL 60439, USA.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Petrova
authors.forename: Marianne E
authors.initials: ME
authors.lastname: Cuff
authors.forename: Ruiying
authors.initials: R
authors.lastname: Wu
authors.forename: Youngchang
authors.initials: Y
authors.lastname: Kim
authors.forename: Denise
authors.initials: D
authors.lastname: Holzle
authors.forename: Andrzej
authors.initials: A
authors.lastname: Joachimiak
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray / Q000379:methods; D003593:Cytoplasm / Q000378:metabolism*; D008027:Light; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012486:Salmonella typhimurium / Q000378:metabolism*; D012542:Scattering, Radiation; D017386:Sequence Homology, Amino Acid; D012997:Solvents / Q000737:chemistry
chemical_list: D012997:Solvents