Virtuelle (Nano) Welten PDB Molecule of the Month 91: Thymine Dimers

Exploring the Structure

Most DNA polymerases have a hard time replicating DNA with pyrimidine dimers. The enzyme on the left, from PDB entry 1rys, is an exception: it is designed to read through damaged DNA. It has a loose active site, so it can easily accommodate the stiff thymine dimer. However, this open active site makes the enzyme rather prone to errors. A more typical DNA polymerase is shown on the right, from PDB entry 1sl2. It tightly enfolds the DNA, and because of this close contact, is very accurate in copying the DNA. However, it has a lot of trouble with damaged bases and works 3,000 times slower on thymine dimers than with a normal DNA.

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