1-beta-D-arabinofuranosyl-5-(E)-(4-azidostyryl)-uracil 5'-triphosphate: synthesis and utilization as a photoaffinity labeling reagent for DNA polymerase alpha from cherry salmon, Oncorhynchus masou.

For developing a photoaffinity labeling reagent for DNA polymerase alpha, we synthesized 1-beta-D-arabinofuranosyl-5-(4-azidostyryl)-uracil 5'-triphosphate [5-(E)-(4-azidostyryl)-araUTP] bearing a photoreactive aryl azido group. This compound was easily decomposed by photolysis by light above 300 nm. This analogue strongly inhibited DNA polymerase alpha purified from cherry salmon, Oncorhynchus masou, testes; the mode of inhibition was mixed when the enzyme reaction was carried out under room light, and was competitive to dTTP in the dark. From the results of photoaffinity labeling experiments using an analogue containing [gamma-32P], it appeared that this analogue could bind to dTTP binding site of DNA polymerase alpha. Thus, this compound should be very useful for analysis of nucleotide binding sites of this enzyme.