Zinc binding stimulates both the 3′-processing
and DNA strand transfer activities of HIV integrase. (A)
Autoradiogram of 3′-processing products of reactions catalyzed by
integrase dialyzed against buffer A containing EDTA or zinc. Reaction
mixtures containing 20 nM DNA substrate and 0.94 μM integrase were
incubated at 37°C for 1 hr. The migration positions of the unreacted
DNA substrate (S) and 3′-processing products (P) are indicated.
(B) Quantitation of the 3′-processing time course shown in
A. ○, Integrase dialyzed against zinc;
•, integrase dialyzed against EDTA. (C)
Autoradiogram of DNA strand transfer products of reactions catalyzed by
integrase dialyzed against buffer A containing EDTA or zinc. Reaction
conditions and labeling are the same as indicated for A,
except that the concentration of DNA substrate was 150 μM.
(D) Quantitation of the DNA strand transfer time course
shown in C. ○, Integrase dialyzed against
zinc; •, integrase dialyzed against EDTA.