Fig. 6. Engineering of the uptake hydrogenase HupSL in Nostoc punctiforme for hydrogen production. Left: N. punctiforme expressing C12P HupS (C12PNp strain) produces H2 in addition to the background production from nitrogenase activity (ΔHupNp strain). Right: the C12P mutation induces a [4Fe–4S] → [3Fe–4S] cluster conversion in the proximal position in HupS, facilitating reverse electron flow towards the active site. The figure was adapted from Raleiras et al.87 with permission from the Royal Society of Chemistry.
