DNA-dependent DNA polymerase
DNA-dependent DNA polymerase (DdDp) plays a role in DNA replication. It catalyzes the synthesis of the DNA strand complementary to a given DNA template.
Viral DdDp are extremely diverse but share common motifs that allow comparison.
Naming: By convention viral polymerases are called RNA/DNA-dependent whereas cellular polymerases are called RNA/DNA-directed.
- DNA nucleotidyltransferase (DNA-dependent) EC 18.104.22.168 RHEA:22508
Viral DdDp are characterized by a conserved motif in which two conserved aspartic acid residues are bound to two magnesium ions. The reaction begins with the deprotonation of primer's 3' OH, in a manner that doesn't require a base
. Subsequently, the 3'-oxygen acts as a nucleophile to attack the phosphate bond and eventually releases a pyrophosphate.