Abstract
Cyanobacteria possess a hight activity of cyclic electron transport. The several pathways have been proposed, but it is not established. NAD(P)H-Quinone Oxidoreductase (NQR) is one of the protein which shows NAD(P)H oxidation activity. In Synechocystis sp. PCC 6803, this gene is registered as a drug resistance gene (drgA). However, it's function is not fully elucidated yet.
NQR shows an NAD(P)H oxidation activity and hence it may participate in cyclic electron transport. To investigate the possibility, we have constructed drgA (slr1719) inactivation mutant and characterized it.
Under high-light intensity, the growth rate of the MT was a half of the WT. For measurement of NAD(P)H oxidation activity, we found an acceptor specific to NQR and inhibitors as well. A possible function of NQR estrimated by measuring redox changes of P700 in cell-free system will also be reported.
