JBC, Vol. 252, Issue 6, 1932-1937, Mar, 1977
Primed and unprimed synthesis of poly (dA-dT) by calf thymus DNA polymerase alpha
D. Henner and J. J. Further
The primed and unprimed synthesis of poly(dA-dA-dT) by calf thymus DNA
polymerase alpha (DNA nucleotidyltransferase; deoxynucleoside triphosphate:
DNA deoxynucleotidyltransferase EC 2.7.7.7) has been compared to
replication of activated DNA. Synthesis of poly(dA-dT) by alpha-polymerase
is both autocatalytic and exponential. The rate of synthesis of poly(dA-dT)
is markedly affected by the Mg2+ concentration and has a higher temperature
optimum than replication of activated DNA, implicating "slippage" as a
necessary part of poly(dA-dT) replication. Calf thymus 24,000-dalton
unwinding protein influences poly(dA-dT) synthesis by increasing both the
exponential rate constant and the rate of linear synthesis. Single-stranded
template poly(dA-dT) is provided alpha-polymerase by both "strand slippage"
and melting by unwinding protein.