Tracking the function of the cytochrome c6-like protein in higher plants

Abstract

The contention that plastocyanin is the only mobile electron donor to photosystem I in higher plants was recently shaken by the discovery of a cytochrome c 6-like protein in Arabidopsis and other flowering plants. However, the genetic and biochemical data presented in support of the idea that the cytochrome c 6 homologue can replace plastocyanin have now been challenged by two complementary studies. This re-opens the debate on the real function(s) of cytochrome c in the chloroplasts of higher plants.