DNA photolysis (from the Greek. Φωτος - light and Greek. Λύνω - weaken, untie, cipher KF 4.1.99.3 ) - one of the DNA repair enzymes , the activation of which occurs under the influence of visible light [1] . DNA photolyase removes photoproducts and pyrimidine-pyrimidine dimers formed in the DNA molecule under the influence of short-wave UV radiation. The process in which the enzyme is involved is called photoreactivation . Such photoreactivating enzymes are found in bacteria and lower eukaryotic organisms , but they were not found in mammalian cells.
| DNA photolyase | |
|---|---|
 | |
| Identifiers | |
| Cipher cf | 4.1.99.3 |
| CAS Number | 37290-70-3 |
| Enzyme bases | |
| Intenz | Intenz view |
| BRENDA | BRENDA entry |
| Expasy | NiceZyme view |
| Metacyc | metabolic pathway |
| Kegg | KEGG entry |
| PRIAM | profile |
| PDB structures | RCSB PDB PDBe PDBj PDBsum |
| Gene ontology | AmiGO • EGO |
| Search | |
| PMC | articles |
| PubMed | articles |
| NCBI | NCBI proteins |
| Cas | 37290-70-3 |
Building
Escherichia coli DNA photoliasis has a molecular weight of 54 kDa. As a cofactor , like all photoliasis, FAD and an additional chromophore act as a light-harvesting antenna. The enzyme acts by electron transfer, in which the reduced FADN is activated by light energy and acts as the electron donor necessary to break the pyrimidine dimer [2] .
Mechanism of Action
When DNA is irradiated with ultraviolet light, either cyclobutane dimers between adjacent pyrimidine bases or pyrimidine photo products such as 6,4-PP are formed in it. Such compounds block DNA replication and must be removed to maintain cell viability. One way to remove pyrimidine dimers is to enzymatically convert them to monomers when exposed to visible light in the wavelength range of 300-600 nm. DNA photolyase forms a stable complex with a pyrimidine dimer and, using the energy of the light absorbed by it, destroys the dimer without breaking the DNA chains.
Being in nature
Photolyases were found in prokaryotes, eukaryotes (protozoa, mold fungi ( yeast ) and some species of insects and higher animals) and archaea. In humans, as in many higher animals, they are absent.
Notes
- ↑ Thiagarajan V. , Byrdin M. , Eker APM , Muller P. , Brettel K. Kinetics of cyclobutane thymine dimer splitting by DNA photolyase directly monitored in the UV // Proceedings of the National Academy of Sciences. - 2011. - May 23 ( t. 108 , No. 23 ). - S. 9402-9407 . - ISSN 0027-8424 . - DOI : 10.1073 / pnas.1101026108 .
- ↑ Sancar A. Structure and function of DNA photolyase and cryptochrome blue-light photoreceptors. (Eng.) // Chemical reviews. - 2003. - Vol. 103, no. 6 . - P. 2203-2237. - DOI : 10.1021 / cr0204348 . - PMID 12797829 .