title: The role of herpes simplex virus ribonucleotide reductase small subunit carboxyl terminus in subunit interaction and formation of iron-tyrosyl center structure.
abstract: Herpes simplex virus ribonucleotide reductase consists of two nonidentical subunits, proteins R1 and R2, which are required together for activity. Active R2 protein contains a tyrosyl free radical and a binuclear iron center. A truncated form of the R2 subunit, lacking 7 amino acid residues in the carboxyl terminus, was constructed, overexpressed in Escherichia coli and purified to homogeneity. In the presence of ferrous iron and oxygen, the truncated protein readily generated similar amounts of tyrosyl free radical as the intact protein. However, the radical showed differences in EPR characteristics in the truncated protein compared with the normal one, indicating an altered structural arrangement of the radical relative to the iron center. The truncated R2* protein was completely devoid of binding affinity to the R1 protein, demonstrating that the subunit interaction is totally dependent on the 7 outermost carboxyl-terminal amino acids of protein R2.
authors.affiliation: Department of Medical Biochemistry and Biophysics, University of Umeå, Sweden.
authors.forename: D
authors.initials: D
authors.lastname: Filatov
authors.forename: R
authors.initials: R
authors.lastname: Ingemarson
authors.forename: A
authors.initials: A
authors.lastname: Gräslund
authors.forename: L
authors.initials: L
authors.lastname: Thelander
mesh_terms: D001483:Base Sequence; D002872:Chromosome Deletion; D003001:Cloning, Molecular; D004279:DNA, Viral / Q000235:genetics* / Q000302:isolation & purification; D004578:Electron Spin Resonance Spectroscopy; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D005609:Free Radicals; D005814:Genes, Viral; D007501:Iron / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009838:Oligodeoxyribonucleotides; D010957:Plasmids; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D015183:Restriction Mapping; D012264:Ribonucleotide Reductases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D018139:Simplexvirus / Q000201:enzymology* / Q000235:genetics; D014443:Tyrosine; D015678:Viral Structural Proteins / Q000235:genetics
chemical_list: D004279:DNA, Viral; D005609:Free Radicals; D046911:Macromolecular Substances; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D015678:Viral Structural Proteins; D014443:Tyrosine; D007501:Iron; D012264:Ribonucleotide Reductases