Re: visible light damage to DNA

["Tom Savin" <lexicon@hotbot.com>]

 I maybe wrong, but I think it was the Setlow(s) out of Oak Ridge Biology Division that performed the original work on thymine dimerization. - Tom
--

On Tue, 8 Aug 2000 13:30:23    Karam, Andrew wrote:
>Following is a response from one of our researchers who investigates
>mutation mechanisms.  Neat stuff!
>
>Andy
>
>-----Original Message-----
>
>Peak and Peak (I forgot their first names) showed that near UV caused some 
>damage (300-~400 nm).  Since DNA absorption tails off around 300 nm this 
>came as a surprise.  At longer wavelengths, the visible light, I don't 
>think any photochemistry occurs via direct interaction with DNA unless you 
>go to high intensity sources (lasers) where multiphoton processes kick 
>in.  Visible light can damage DNA indirectly via a chromophore that absorbs 
>visible light and subsequently passing on the excitation to O2 (singlet 
>oxygen) which then can react with DNA (albeit very slowly).  The latter is 
>the basis for photodynamic therapy.
>
>
>Andrew Karam, CHP              (716) 275-1473 (voice)
>Radiation Safety Officer          (716) 275-3781 (office)
>University of Rochester           (716) 256-0365 (fax)
>601 Elmwood Ave. Box HPH   Rochester, NY  14642
>
>Andrew_Karam@URMC.Rochester.edu
>http://Intranet.urmc.rochester.edu/RadiationSafety
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