title: Structure of an mRNA capping enzyme bound to the phosphorylated carboxy-terminal domain of RNA polymerase II.
abstract: The 2.7 A structure of Candida albicans RNA guanylyltransferase Cgt1 cocrystallized with a carboxy-terminal domain (CTD) peptide composed of four Ser5-PO4 YSPTSPS heptad repeats illuminates distinct CTD-docking sites localized to the Cgt1 N-terminal nucleotidyl transferase domain. Tyr1, Pro3, Pro6, and Ser5-PO4 side chains from each of two YSPTSPS repeats contribute to the interface. Comparison to the Pin1-CTD structure shows that the CTD can assume markedly different conformations that are templated by particular binding partners. Structural plasticity combined with remodeling of CTD primary structure by kinases and phosphatases provides a versatile mechanism by which the CTD can recruit structurally dissimilar proteins during transcription. A binding site for the RNA triphosphatase component of the capping apparatus was also uncovered within the Cgt1 OB domain.
authors.affiliation: Biochemistry Department, Structural Biology Program, Weill Medical College of Cornell University, New York, NY 10021, USA.
authors.forename: Carme
authors.initials: C
authors.lastname: Fabrega
authors.forename: Vincent
authors.initials: V
authors.lastname: Shen
authors.forename: Stewart
authors.initials: S
authors.lastname: Shuman
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Lima
mesh_terms: D017766:Acid Anhydride Hydrolases / Q000378:metabolism; D000595:Amino Acid Sequence; D001665:Binding Sites; D002176:Candida albicans / Q000201:enzymology / Q000235:genetics; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D009713:Nucleotidyltransferases / Q000737:chemistry* / Q000378:metabolism; D010766:Phosphorylation; D017354:Point Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012315:RNA Caps; D012319:RNA Polymerase II / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D000098556:mRNA Guanylyltransferases
chemical_list: D012315:RNA Caps; D009713:Nucleotidyltransferases; D012319:RNA Polymerase II; D000098556:mRNA Guanylyltransferases; D017766:Acid Anhydride Hydrolases; C023090:RNA triphosphatase