Chlorophyll a Dimers Bound in the Water-Soluble Protein BoWSCP Photosensitize the Reduction of Cytochrome c

When bound to water-soluble proteins of the WSCP family, chlorophyll molecules form dimers structurally similar to the “special pair” of chlorophylls (bacteriochlorophylls) in photosynthetic reaction centers. Being exposed to red light (λ ≥ 650 nm) in oxygen-free solutions, chlorophyll a dimers harbored by BoWSCP holoproteins (from Brassica oleracea var . botrytis ) have sensitized the reduction of cytochrome c . According to absorption and circular dichroism spectroscopy data, the photochemical process did not significantly impair the structure of chlorophyll a molecules as well as their dimers harbored by BoWSCP protein. Adding tris (hydroxymethyl)aminomethane as an electron donor for chlorophyll recovery stimulated the photoreduction of cytochrome c .