Schmidt, G. and Siebzehnrübl, S. and Fischer, R. and Rüdiger, W. and Scheer, Hugo and Schirmer, T. and Bode, W. and Huber, R.
ZZE-Configuration of chromophore ß-153 in C-phycocyanin from Mastigocladus laminosus.
In: Zeitschrift für Naturforschung C, Vol. 42c: pp. 845-848
The photochemistry of C-phycocyanin has been studied after denaturation in the dark. It shows
an irreversible reaction which has characteristics of a Ζ,Ζ,Ε- to Z,Z,Z-isomerization of dihydrobilins.
Its amplitude depends on the reaction conditions, with a maximum corresponding to 15%
conversion of one of the three PC chromophores. This chromophore is suggested to be ß-153, for
which recent X-ray data T. Schirmer, W. Bode, and R. Huber, J. Mol. Biol., submitted, show
ring D being highly twisted out of the plane of the other rings. During unfolding, there is thus a
probability of falling into the photochemically labile Z,Z,^-configuration.