In vitro assembly of a β₂ cytochrome b₅₅₉‐like complex from the chemically synthesised β‐subunit encoded by the Synechocystis sp. 6803 psbF gene

The alpha- and beta-subunits of cytochrome b559 encoded by the psbE and psbF gene, respectively, are essential components of photosystem II. The exact structure of this cytochrome is not yet known. The beta-subunit of the Synechocystis sp. 6803 cytochrome b559 complex was synthesised by means of solid-phase peptide synthesis. Under reducing conditions, two beta-peptide molecules could be assembled specifically with one haem to form a beta2 cytochrome b559-like complex. The spectral properties and the midpoint redox potential (48+/-5 mV) of the in vitro assembled beta2 cytochrome are nearly identical to those of the low potential form of the native cytochrome b559.