2Department of Molecular Biology, School of Biology, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (095) 939-4658
* To whom correspondence should be addressed.
Received June 4, 1998; Revision received June 25, 1998
The iron chelator 2,2'-dipyridyl (0.2 mM) more than fourfold increased the concentration of protoporphyrin IX and also of its zinc-containing complex in mitochondria of the yeast Saccharomyces cerevisiae. Protoporphyrin IX and a chlorine derivative of protoporphyrin IX which fluoresces at 670-675 nm were found in isolated plasma membranes of the yeast grown in the presence of 0.2 mM 2,2'-dipyridyl. The accumulation of endogenous porphyrins resulted in intensification of lipid photoperoxidation in mitochondria and plasma membranes and in a dramatically increased sensitivity of the cells to visible light (400-600 nm). The relative contribution of photodestruction of subcellular structures to photoinduced cell inactivation is discussed.
KEY WORDS: protoporphyrin IX, 2,2'-dipyridyl, photosensitized inactivation, lipid photoperoxidation