Premium
PHOTOREACTIVATION IN A phrB MUTANT OF Escherichia coli K‐12: EVIDENCE FOR THE ROLE OF A SECOND PROTEIN IN PHOTOREPAIR
Author(s) -
Dorrell N.,
Ahmed A. H.,
Moss S. H.
Publication year - 1993
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1993.tb04979.x
Subject(s) - photolyase , pyrimidine dimer , escherichia coli , shuttle vector , mutant , biology , gene , genetics , dna repair , dna , drosophila melanogaster , enzyme , microbiology and biotechnology , nucleotide excision repair , biochemistry , vector (molecular biology) , recombinant dna
In Escherichia coli , the light‐dependent repair of pyrimidine dimers in UV‐irradiated DNA is now accepted as being due to enzymatic photoreactivation (PR) by a 50 kDa enzyme, photolyase (EC 4.1.99.3). The gene for this enzyme has been mapped at 16.2 min and designated phr . This gene was earlier described as phr B, another locus phr A having been proposed in association with PR. The relevance of the putative phr A gene has now been placed in doubt. The recent report of the discovery of a photoreactivating enzyme in Drosphila melanogaster . which specifically repairs pyrimidine (6–4) pyrimidone photoproducts ([6–4] photoproducts), and that E. coli does possess a protein with specific affinity for the (6–4) photoproduct, has cast new light on the prospective role of phr A in PR. We have determined the nucleotide sequence of the putative phr A gene, which suggests it codes for a protein of 38 kDa. When the putative phr A gene was cloned into an expression vector and transformed into a phr A phr B mutant of E. coli , a level of photorepair was observed, which could correspond to repair of (6–4) photoproducts.