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.

Primer:

RNA-3'OH
DNA-3'OH
primer-indepedent

Enzymatic reaction:

DNA nucleotidyltransferase (DNA-dependent) EC 2.7.7.7 RHEA:22508

Mechanism 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.