SYNTHESIS OF THE RHODOPSEUDOMONAS-VIRIDIS HOLO-CYTOCHROME-C2 IN PARACOCCUS-DENITRIFICANS

The gene encoding the Rhodopseudomonas viridis cytochrome C2 (cycA) ha s been introduced on a broad host range vector into Paracoccus denitri ficans, leading to high-level expression of the holo-cytochrome with t he heme moiety covalently attached to the apoprotein. The cytochrome w as demonstrated to reside in the periplasmic space of the host cell. I n contrast to R. viridis, aerobic rather than anaerobic growth conditi ons led to higher production levels of the holo-cytochrome in P. denit rificans. This heterologous expression system provides a suitable gene tic background for the functional expression and mutagenesis of polype ptides involved in bacterial photosynthesis, offering the possibility of detailed structural and functional investigation.