{PDOC00832}
{PS01083; DNA_PHOTOLYASES_2_1}
{PS01084; DNA_PHOTOLYASES_2_2}
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* DNA photolyases class 2 signatures *
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Deoxyribodipyrimidine photolyase (EC 4.1.99.3) (DNA photolyase) [1,2] is a DNA
repair enzyme. It   binds to UV-damaged DNA containing  pyrimidine dimers and,
upon absorbing  a  near-UV photon (300 to 500 nm), breaks the cyclobutane ring
joining the  two  pyrimidines   of the dimer. DNA photolyase is an enzyme that
requires two  choromophore-cofactors  for  its  activity:  a reduced FADH2 and
either 5,10-methenyltetrahydrofolate  (5,10-MTFH)  or an oxidized 8-hydroxy-5-
deazaflavin (8-HDF)  derivative  (F420). The folate or deazaflavin chromophore
appears to  function  as an antenna, while the FADH2 chromophore is thought to
be responsible  for  electron  transfer. On the basis of sequence similarities
[3] DNA photolyases can be grouped into two classes. The second class contains
enzymes from  Myxococcus  xanthus,  methanogenic archaebacteria, insects, fish
and marsupial  mammals.  It is not yet known  what second cofactor is bound to
class 2 enzymes.

There are  a  number  of conserved  sequence  regions in all known class 2 DNA
photolyases, especially in  the  C-terminal  part.  We  selected  two of these
regions as signature patterns.

-Consensus pattern: F-x-E-E-x-[LIVM](2)-R-R-E-L-x(2)-N-F
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Consensus pattern: G-x-H-D-x(2)-W-x-E-R-x-[LIVM]-F-G-K-[LIVM]-R-[FY]-M-N
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Note: See also the entry for class 1 DNA photolyases (see <PDOC00331>).

-Last update: November 1995 / First entry.

[ 1] Sancar G.B., Sancar A.
     Trends Biochem. Sci. 12:259-261(1987).
[ 2] Jorns M.S.
     "DNA photorepair: chromophore composition and function in two classes
     of DNA photolyases."
     Biofactors 2:207-211(1990).
     PubMed=2282137
[ 3] Yasui A., Eker A.P.M., Yasuhira S., Yajima H., Kobayashi T., Takao M.,
     Oikawa A.
     "A new class of DNA photolyases present in various organisms including
     aplacental mammals."
     EMBO J. 13:6143-6151(1994).
     PubMed=7813451

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