One of Two NTP Binding Sites in Poliovirus RNA Polymerase Required for RNA Replication

摘要: The poliovirus RNA-dependent RNA polymerase (3Dpol) has been shown to contain two NTP binding sites by chemical cross-linking of oxidized nucleotide the intact protein. Only one site (Lys-61) was be essential for chain elongation activity purified enzyme; however, a full-length viral RNA, coding an altered lysine residue (K276L) in second site, generated virus with minute plaque phenotype that rapidly reverted wild-type Arg-276 replacing Leu-276 3D. Viruses leucine substitutions other positions their proteins grew phenotype. To test significance 3Dpol (wild-type), leucine, or arginine at 276 and tested using 32P-oxidized GTP. Analysis cyanogen bromide peptides each 3D preparation showed had severely reduced mu276(Leu) but not revertant mu276(Arg), despite reported requirement reaction. eliminate possibility GTP cross-linked Arg 276, model system designed unmodified amino acid acetylated (alpha-amino) Cross-linking lysine, arginine, observed thus eliminating could We conclude is residues than (278 283), these no bearing on replication virus. Nucleotide only including Lys-61 replication.