Friday, July 22, 2011

Watching damage control in real time

Today I read a nice Nature paper Dynamics and mechanism of repair of ultraviolet-induced (6–4) photoproduct by photolyase from Dongping Zhong's group.

One way that UV can damage DNA (and cause mutations, kill cells, and cause skin cancer) is by fusing together two adjacent pyrimidine rings to produce a molecule 6-4PP.
The figure to the right (taken from here) shows the associated rearrangement of atoms.

What is amazing is that nature has a way to repair this mutation involving a flavoenzyme called photolyase. This paper elucidates (using ultrafast laser spectroscopy) the repair mechanism which is summarised in the schematic below. It contains steps involving electron transfer and proton transfer.

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