title: Crystal structure of the simian virus 40 large T-antigen origin-binding domain.
abstract: The origins of replication of DNA tumor viruses have a highly conserved feature, namely, multiple binding sites for their respective initiator proteins arranged as inverted repeats. In the 1.45-angstroms crystal structure of the simian virus 40 large T-antigen (T-ag) origin-binding domain (obd) reported herein, T-ag obd monomers form a left-handed spiral with an inner channel of 30 angstroms having six monomers per turn. The inner surface of the spiral is positively charged and includes residues known to bind DNA. Residues implicated in hexamerization of full-length T-ag are located at the interface between adjacent T-ag obd monomers. These data provide a high-resolution model of the hexamer of origin-binding domains observed in electron microscopy studies and allow the obd's to be oriented relative to the hexamer of T-ag helicase domains to which they are connected.
authors.affiliation: Tufts University School of Medicine, Department of Biochemistry, 136 Harrison Avenue, Boston, Massachusetts 02111, USA.
authors.forename: Gretchen
authors.initials: G
authors.lastname: Meinke
authors.forename: Peter A
authors.initials: PA
authors.lastname: Bullock
authors.forename: Andrew
authors.initials: A
authors.lastname: Bohm
mesh_terms: D000595:Amino Acid Sequence; D000957:Antigens, Viral, Tumor / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D018741:Replication Origin / Q000235:genetics*; D013539:Simian virus 40 / Q000737:chemistry* / Q000235:genetics
chemical_list: D000957:Antigens, Viral, Tumor; D004279:DNA, Viral