title: Flexible segments modulate co-folding of dUTPase and nucleocapsid proteins.
abstract: The homotrimeric fusion protein nucleocapsid (NC)-dUTPase combines domains that participate in RNA/DNA folding, reverse transcription, and DNA repair in Mason-Pfizer monkey betaretrovirus infected cells. The structural organization of the fusion protein remained obscured by the N- and C-terminal flexible segments of dUTPase and the linker region connecting the two domains that are invisible in electron density maps. Small-angle X-ray scattering reveals that upon oligonucleotide binding the NC domains adopt the trimeric symmetry of dUTPase. High-resolution X-ray structures together with molecular modeling indicate that fusion with NC domains dramatically alters the conformation of the flexible C-terminus by perturbing the orientation of a critical beta-strand. Consequently, the C-terminal segment is capable of double backing upon the active site of its own monomer and stabilized by non-covalent interactions formed with the N-terminal segment. This co-folding of the dUTPase terminal segments, not observable in other homologous enzymes, is due to the presence of the fused NC domain. Structural and genomic advantages of fusing the NC domain to a shortened dUTPase in betaretroviruses and the possible physiological consequences are envisaged.
authors.affiliation: Institute of Enzymology, BRC, Hungarian Academy of Sciences, Budapest, Karolina út 29, H-1113, Hungary.
authors.forename: Veronika
authors.initials: V
authors.lastname: Németh-Pongrácz
authors.forename: Orsolya
authors.initials: O
authors.lastname: Barabás
authors.forename: Mónika
authors.initials: M
authors.lastname: Fuxreiter
authors.forename: István
authors.initials: I
authors.lastname: Simon
authors.forename: Iva
authors.initials: I
authors.lastname: Pichová
authors.forename: Michalea
authors.initials: M
authors.lastname: Rumlová
authors.forename: Helena
authors.initials: H
authors.lastname: Zábranská
authors.forename: Dmitri
authors.initials: D
authors.lastname: Svergun
authors.forename: Maxim
authors.initials: M
authors.lastname: Petoukhov
authors.forename: Veronika
authors.initials: V
authors.lastname: Harmat
authors.forename: Eva
authors.initials: E
authors.lastname: Klement
authors.forename: Eva
authors.initials: E
authors.lastname: Hunyadi-Gulyás
authors.forename: Katalin F
authors.initials: KF
authors.lastname: Medzihradszky
authors.forename: Emese
authors.initials: E
authors.lastname: Kónya
authors.forename: Beáta G
authors.initials: BG
authors.lastname: Vértessy
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D016093:Mason-Pfizer monkey virus / Q000201:enzymology* / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D019590:Nucleocapsid Proteins / Q000737:chemistry* / Q000235:genetics; D020815:Polyproteins / Q000737:chemistry; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011755:Pyrophosphatases / Q000737:chemistry* / Q000235:genetics; D016415:Sequence Alignment; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics
chemical_list: D019590:Nucleocapsid Proteins; D020815:Polyproteins; D014764:Viral Proteins; D011755:Pyrophosphatases; C020020:dUTP pyrophosphatase