07 March 1997
Vol 275, Issue 5305

About The Cover

The thymine dimer is a DNA lesion caused by exposure to ultraviolet light. Shining visible light on a rhodium complex stacked in DNA leads to repair of this lesion by electron transfer. In the DNA assembly illustrated, where the rhodium (yellow) is tethered and stacked 26 angstroms from the thymine dimer (red), repair is still effected by long-range electron transfer (green). In this reaction, the stacked DNA base pairs act as a conduit for chemistry at a distance. See 1465 and the News story on 1420. [Image: P. J. Dandliker]