title: Clustering of OB-fold domains of the partner protease complexed with trimeric stomatin from Thermococcales.
abstract: The C-terminal soluble domain of stomatin operon partner protein (STOPP) of the hyperthermophilic archaeon Pyrococcus horikoshii has an oligonucleotide binding-fold (OB-fold). STOPP lacks the conserved surface residues necessary for binding to DNA/RNA. A tryptophan (W) residue is conserved instead at the molecular surface. Solvent-accessible W residues are often found at interfaces of protein-protein complexes, which suggested the possibility of self-assembling of STOPP. Protein-protein interactions among the C-terminal soluble domains of STOPP PH1510 (1510-C) were then analyzed by chemical linking and blue native polyacrylamide gel electrophoresis (BN-PAGE) methods. These results suggest that the soluble domains of STOPP could assemble into homo-oligomers. Since hexameric subcomplex I from archaeal proteasome consists of coiled-coil segments and OB-fold domains, molecular modeling of 1510-C was performed using hexameric subcomplex I as a template. Although 1510-C is a comparatively small polypeptide consisting of approximately 60 residues, numerous salt bridges and hydrophobic interactions were observed in the predicted hexamer of 1510-C, suggesting the stability of the homo-oligomeric structure. This oligomeric property of STOPP may be favorable for triplicate proteolysis of the trimer of prokaryotic stomatin.
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan.
authors.forename: Hideshi
authors.initials: H
authors.lastname: Yokoyama
authors.forename: Eriko
authors.initials: E
authors.lastname: Matsui
authors.forename: Kana
authors.initials: K
authors.lastname: Hiramoto
authors.forename: Patrick
authors.initials: P
authors.lastname: Forterre
authors.forename: Ikuo
authors.initials: I
authors.lastname: Matsui
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D009876:Operon; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D043902:Pyrococcus horikoshii / Q000201:enzymology / Q000378:metabolism*; D014364:Tryptophan / Q000235:genetics / Q000378:metabolism
chemical_list: D019843:Archaeal Proteins; D014364:Tryptophan; D046988:Proteasome Endopeptidase Complex