KaiA promotes expression and activity of endogenous Hox hydrogenase (H2ase).
(A) kaiA-enhanced mRNA microarray profiles of all H2ase subunits and H2ase maturation genes (as denoted) in the kaiA-overexpressing strain with (red) or without IPTG (blue).
(B) Hydrogenase activity increases in the {ATG}kaiA-OX strain relative to the wild-type (WT) strain in the absence or presence of IPTG induction. Data are represented as mean +/− SD from three independent experiments and analyzed with t-test. Note that the {ATG}kaiA overexpression construct is slightly “leaky”, and even at 0 μM IPTG, there is some extra expression of KaiA above that in WT.
(C) KaiA causes constantly high levels of hydrogenase activities under continuous light conditions. Following a 12h of dark pulse, the endogenous hydrogenase activities were measured from samples of the WT and {ATG}kaiA-OX strains at the indicated times in LL.