title: Domain structure of the Acetogenium kivui surface layer revealed by electron crystallography and sequence analysis.
abstract: The three-dimensional structure of the Acetogenium kivui surface layer (S-layer) has been determined to a resolution of 1.7 nm by electron crystallographic techniques. Two independent reconstructions were made from layers negatively stained with uranyl acetate and Na-phosphotungstate. The S-layer has p6 symmetry with a center-to-center spacing of approximately 19 nm. Within the layer, six monomers combine to form a ring-shaped core surrounded by a fenestrated rim and six spokes that point towards the axis of threefold symmetry and provide lateral connectivity to other hexamers in the layer. The structure of the A. kivui S-layer protein is very similar to that of the Bacillus brevis middle wall protein, with which it shares an N-terminal domain of homology. This domain is found in several other extracellular proteins, including the S-layer proteins from Bacillus sphaericus and Thermus thermophilus, Omp alpha from Thermotoga maritima, an alkaline cellulase from Bacillus strain KSM-635, and xylanases from Clostridium thermocellum and Thermoanaerobacter saccharolyticum, and may serve to anchor these proteins to the peptidoglycan. To our knowledge, this is the first example of a domain conserved in several S-layer proteins.
authors.affiliation: Max-Planck-Institut für Biochemie, Martinsried, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Lupas
authors.forename: H
authors.initials: H
authors.lastname: Engelhardt
authors.forename: J
authors.initials: J
authors.lastname: Peters
authors.forename: U
authors.initials: U
authors.lastname: Santarius
authors.forename: S
authors.initials: S
authors.lastname: Volker
authors.forename: W
authors.initials: W
authors.lastname: Baumeister
mesh_terms: D000595:Amino Acid Sequence; D001407:Bacillus / Q000737:chemistry / Q000648:ultrastructure; D001419:Bacteria / Q000737:chemistry*; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000648:ultrastructure; D002462:Cell Membrane / Q000737:chemistry* / Q000648:ultrastructure; D003013:Clostridium / Q000737:chemistry / Q000648:ultrastructure; D003461:Crystallography; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid; D016963:Thermus thermophilus / Q000737:chemistry / Q000648:ultrastructure
chemical_list: D001425:Bacterial Outer Membrane Proteins; D046911:Macromolecular Substances