J. Biol. Chem., Vol. 265, Issue 13, 7112-7115, May, 1990
Herpes simplex virus type 1 DNA polymerase. Mechanism-based affinity chromatography
JE Reardon
Experimental Therapy Division, Wellcome Research Laboratories, Research Triangle Park, North Carolina 27709.
The potent inhibition of herpes simplex type 1 (HSV-1) DNA polymerase by
acyclovir triphosphate has previously been shown to be due to the formation
of a dead-end complex upon binding of the next 2'- deoxynucleoside
5'-triphosphate encoded by the template after incorporation of acyclovir
monophosphate into the 3'-end of the primer (Reardon, J. E., and Spector,
T. (1989) J. Biol. Chem. 264, 7405-7411). This mechanism of inhibition of
HSV-1 DNA polymerase has been used here to design an affinity column for
the enzyme. A DNA hook template-primer containing an acyclovir
monophosphate residue on the 3'-primer terminus has been synthesized and
attached to a resin support. In the absence of added nucleotides, the
column behaves as a simple DNA-agarose column, and HSV-1 DNA polymerase can
be chromatographed using a salt gradient. The presence of the next required
nucleotide encoded by the template (dGTP) increases the affinity of HSV-1
DNA polymerase for the acyclovir monophosphate terminal primer-template
attached to the resin, and the enzyme is retained even in the presence of 1
M salt. The enzyme can be eluted from the column with a salt gradient after
removal of the nucleotide from the buffer. Traditionally, the affinity
purification of an enzyme relies on elution by a salt gradient, pH
gradient, or more selectively by addition of a competing ligand
(substrate/inhibitor) to the elution buffer. In the present example,
elution of HSV-1 polymerase is facilitated by removal of the substrate from
the buffer. This represents an example of mechanism-based affinity
chromatography.