An error-prone family Y DNA polymerase (DinB homolog from Sulfolobus solfataricus) uses a 'steric gate' residue for discrimination against ribonucleotides.

ABSTRACT: DNA polymerases of the A and B families, and reverse transcriptases, share a common mechanism for preventing incorporation of ribonucleotides: a highly conserved active site residue obstructing the position that would be occupied by a 2' hydroxyl group on the incoming nucleotide. In the family Y (lesion bypass) polymerases, the enzyme active site is more open, with fewer contacts to the DNA and nucleotide substrates. Nevertheless, ribonucleotide discrimination by the DinB homolog (Dbh) DNA polymerase of Sulfolobus solfataricus is as stringent as in other polymerases. A highly conserved aromatic residue (Phe12 in Dbh) occupies a position analogous to the residues responsible for excluding ribonucleotides in other DNA polymerases. The F12A mutant of Dbh incorporates ribonucleoside triphospha

SUBMITTER: DeLucia AM 

PROVIDER: S-EPMC165950 | biostudies-literature | 2003 Jul

REPOSITORIES: biostudies-literature