Novel ribonucleotide discrimination in the RNA polymerase-like two-barrel catalytic core of Family D DNA polymerases.

摘要: Family D DNA polymerase (PolD) is the essential replicative for duplication of most archaeal genomes. PolD contains a unique two-barrel catalytic core absent from all other families but found in RNA polymerases (RNAPs). While has an ancestral core, its active site evolved ability to discriminate against ribonucleotides. Until now, mechanism by prevent ribonucleotide incorporation was unknown. In families, steric gate residue prevents incorporation. this work, we identify two consensus acidic (a) and basic (b) motifs shared across entire nucleotide superfamily, selectivity (s) motif specific versus RNAPs. A novel histidine (H931 Thermococcus sp. 9°N PolD) s-motif both promotes efficient dNTP Further, H931A mutant abolishes discrimination readily incorporates variety 2' modified nucleotides. Taken together, construct first putative bound model provide structural functional evidence emergence replication through evolution RNAP core.