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PDBsum entry 3g0r
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Hydrolase/DNA
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PDB id
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3g0r
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References listed in PDB file
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Key reference
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Title
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Crystal structure analysis of DNA uridine endonuclease mth212 bound to DNA.
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Authors
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K.Lakomek,
A.Dickmanns,
E.Ciirdaeva,
L.Schomacher,
R.Ficner.
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Ref.
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J Mol Biol, 2010,
399,
604-617.
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PubMed id
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Abstract
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The reliable repair of pre-mutagenic U/G mismatches originated from hydrolytic
cytosine deamination is crucial for the maintenance of the correct genomic
information. In most organisms any uracil base in DNA is attacked by uracil DNA
glycosylases (UDGs), but at least in Methanothermobacter thermautotrophicus
DeltaH an alternative strategy has evolved. The exonuclease III homologue Mth212
from the thermophilic archaeon M. thermautotrophicus DeltaH exhibits a DNA
uridine endonuclease activity in addition to the apyrimidinic / apurinic site
(AP) endonuclease and 3'-->5'exonuclease functions. Mth212 alone compensates
for the lack of a UDG in a single step reaction thus substituting the two step
pathway that requires the consecutive action of UDG and AP endonuclease. In
order to gain deeper insight into the structural basis required for the specific
uridine recognition by Mth212, we have characterized the enzyme by means of
X-ray crystallography. Structures of Mth212 wild-type or mutant proteins either
alone or in complex with DNA substrates and products have been determined to a
resolution of up to 1.2 A suggesting key residues for the uridine endonuclease
activity. The insertion of the side chain of Arg209 into the DNA helical base
stack resembles interactions observed in human UDG and seems to be crucial for
the uridine recognition. In addition, Ser171, Asn153 and Lys125 in the substrate
binding pocket appear to have important functions in the discrimination of
aberrant uridine against naturally occuring thymidine and cytosine residues in
double-stranded DNA.
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Secondary reference #1
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Title
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The methanothermobacter thermautotrophicus exoiii homologue mth212 is a DNA uridine endonuclease.
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Authors
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J.Georg,
L.Schomacher,
J.P.Chong,
A.I.Majerník,
M.Raabe,
H.Urlaub,
S.Müller,
E.Ciirdaeva,
W.Kramer,
H.J.Fritz.
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Ref.
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Nucleic Acids Res, 2006,
34,
5325-5336.
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PubMed id
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