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Search The CSA
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Catalytic Site Atlas

CSA LITERATURE entry for 1dnp

E.C. namedeoxyribodipyrimidine photo-lyase
SpeciesEscherichia coli (Bacteria)
E.C. Number (IntEnz) 4.1.99.3
CSA Homologues of 1dnpThere are 26 Homologs
CSA Entries With UniProtID P00914
CSA Entries With EC Number 4.1.99.3
PDBe Entry 1dnp
PDBSum Entry 1dnp
MACiE Entry M0183

Literature Report

IntroductionDNA is very sensitive to UV-radiation and other damaging agents. One result of UV radiation is the production of cyclobutane-type dimers formed from adjacent pyrimidine bases which block replication and thus have cytotoxic and mutagenic effects. Such damage is, however, effectively repaired by photolyases. Photoreactivation comprises several steps: damage recognition and binding of photolyase to DNA, photon absorption, interchromophoric energy transfer and electron transfer from the chromophore to the DNA. Two cofactors are required by the enzyme, the first, FAD, is essential for the light dependent repair process whilst the second (either 8-hydroxy-5-deazaflavin or 5,10-methenyltetrahydro-folic acid) acts as a light harvesting chromophore. The photolyases are divided into two groups according to their second cofactor.
MechansimThe reaction can be divided into five steps. First the light-harvesting cofactor absorbs a photon then the excitation energy is transferred to the catalytic cofactor. Thirdly an electron is transferred to the pyridimine dimer in the substrate. Fourthly the C5-C5 and C6-C6 sigma bonds of the cyclobutane ring are broken and finally the electron is transferred back to the flavin and the now intact DNA dissociates from the enzyme. The inert neutral radical form of FADH. created can be reactivated by irradiation of the enzyme with white light which causes electron transfer from Trp306. This form is actually able to split the dipyridimine under 280nm light by electron transfer from Trp277.
Reaction

Catalytic Sites for 1dnp

Annotated By Reference To The Literature - Site 1 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
TrpA306307macie:sideChain
TrpA359360macie:sideChain
TrpA382383macie:sideChain

Annotated By Reference To The Literature - Site 2 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
TrpB306307macie:sideChain
TrpB359360macie:sideChain
TrpB382383macie:sideChain

Literature References

Notes:
Park HW
Crystal structure of DNA photolyase from Escherichia coli.
Science 1995 268 1866-1872
PubMed: 7604260
Tamada T
Crystal structure of DNA photolyase from Anacystis nidulans.
Nat Struct Biol 1997 4 887-891
PubMed: 9360600
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