KINETICS OF PYRIMIDINE(6-4)PYRIMIDONE PHOTOPRODUCT REPAIR IN ESCHERICHIA-COLI

We compared the removal of pyrimidine(6-4)pyrimidone photoproducts [(6 -4) photoproducts] and cyclobutane pyrimidine dimers (CPDs) from the g enome of repair-proficient Escherichia coli, using monoclonal antibodi es specific for each type of lesion, We found that (6-4) photoproducts were removed at a higher rate than CPDs in the first 30 min following a moderate UV dose (40 J/m(2)). The difference in rates was less than that typically reported for cultured mammalian cells, in which the re moval of (6-4) photoproducts is far more rapid than that of CPDs.