Disease relevance of phr

• For functional analysis P.tridactylis photolyase was expressed and purified as glutathione S-transferase fusion protein from Escherichia coli cells [1].

High impact information on phr

• Two types of photolyase are known, one specific for cyclobutane pyrimidine dimers (CPD photolyase) and another specific for pyrimidine (6-4) pyrimidone photoproducts[(6-4)photolyase] [2].
• In the present study a gene encoding the Drosophila(6-4)photolyase ws cloned, and the deduced amino acid sequence of the product was found to be similar to the CPD photolyase and to the blue-light photoreceptor of plants [2].
• DNA photolyase specifically repairs UV light-induced cyclobutane-type pyrimidine dimers in DNA through a light-dependent reaction mechanism [1].
• Furthermore, we found in the archaebacterium Methanobacterium thermoautotrophicum a gene similar to the higher eukaryote photolyase genes, but we could not obtain evidence for the presence of a homologous gene in the human genome [1].
• Furthermore, we provide evidence that the (6-4) photoproduct photolyase converts the photoproduct to unmodified bases probably through an oxetane intermediate [3].

Chemical compound and disease context of phr

• 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) [4].

Biological context of phr

• A partial deficiency in the excision repair of pyrimidine dimers originally observed in the mus304 mutants is now attributed to the presence of a secondary phr mutation in that stock [5].
• The phr cDNA hybridized to band 44C-D of Drosophila polytene chromosome, equivalent to the locus of the phr- gene [6].
• The phr cDNA was cloned from D. melanogaster; it has an open reading frame to encode a 61,483-Da protein [6].
• The phylogenetic analysis suggested that the ancestral gene of the family had encoded CPD photolyase and that the gene duplication of the ancestral proteins had occurred at least eight times before the divergence between eubacteria and eukaryotes [7].
• In the present study, it was found that the duration of the induced photorepair ability for cyclobutane pyrimidine dimers was longer than that for (6-4) photoproducts, suggesting the presence of different photolyases for repair of these two major forms of DNA damage [8].

Associations of phr with chemical compounds

• Since the mus306 and mus308 stocks also carry secondary phr mutations, their partial deficiency in repair of pyrimidine dimers may also be the result of that secondary mutation [5].
• Similar to other members of the photolyase/blue-light photoreceptor family, both proteins were found to contain FAD and a pterin cofactor [9].
• Cryptochromes are flavin- and folate-containing blue-light photoreceptors with a high degree of similarity to DNA photolyase, which repairs ultraviolet-induced DNA damage using blue light to initiate the repair reaction [10].

Other interactions of phr

• Accordingly, the Drosophila mutations that are now definitively associated with defects in the incision step of pyrimidine dimers removal are mei-9, mus201 and phr [5].

References