Specific interaction between damaged bases in DNA and repair enzymes (第9回公開シンポジウムモデルDNA損傷と変異機構)

概要

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T4 endonuclease V is a DNA repair enzyme from bacteriophage T4 which catalyzes the first reaction step of the pyrimidine dimer specific base excision repair pathway. The crystal structure of the enzyme complexed with a duplex DNA substrate, containing a thymine dimer, has been determined at 2.75Å resolution. The atomic structure of the complex reveals the unique conformation of the DNA duplex, which exhibits a sharp kink with a 60° inclination at the central thymine dimer. This kink divides the duplex into two B-DNA regions, each of which makes extensive polar interactions with the basic concave surface of the enzyme. The adenine base complementary to the 5' side of the thymine dimer is completely flipped out of the DNA duplex and is trapped in a cavity on the protein surface. These structural features allow an understanding of the catalytic mechanism and implicate a general mechanism of how other repair enzymes recognize damaged DNA duplexes.
日本環境変異原学会の論文
1998-10-31