title: In vitro self-assembly of the S layer subunits from Clostridium difficile GAI 0714 into tetragonal arrays.
abstract: Regularly arrayed surface component (S layer) of Clostridium difficile strain GAI 0714 was isolated with 4 M guanidine hydrochloride from the cell wall of the organism, and examined for self-assembly in vitro. The S layer was composed of two different protein subunits with molecular weights of 32 kDa and 45 kDa. Optical diffraction analysis revealed that the morphological units of both native and self-assembled S layer were essentially identical and composed of a rhombus possessing each side of 8.1 nm and interior angle of 88 degrees. The self-assembly of S layer subunits were induced in the presence of divalent cations such as Ca2+ or Zn2+, but Ba2+ or monovalent cations including K+, Na+ and Li+ failed to induce self-assembly. These results suggest that Ca+2 or Zn+2 may act as bridges to link negatively charged surface subunits.
authors.affiliation: Department of Food Microbiology, School of Medicine, University of Tokushima, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Takumi
authors.forename: Y
authors.initials: Y
authors.lastname: Endo
authors.forename: T
authors.initials: T
authors.lastname: Koga
authors.forename: T
authors.initials: T
authors.lastname: Oka
authors.forename: Y
authors.initials: Y
authors.lastname: Natori
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000302:isolation & purification; D001426:Bacterial Proteins; D016360:Clostridioides difficile / Q000737:chemistry* / Q000145:classification / Q000648:ultrastructure; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D008562:Membrane Glycoproteins; C055764:S-layer proteins