2011 Volume 51 Issue 2 Pages 066-071
Protochlorophyllide (Pchlide) reduction is the final step to make up the spectroscopic properties of chlorophyll a in biosynthesis of chlorophyll. During evolution, photosynthetic organisms have invented two structurally unrelated Pchlide reductases; light-dependent Pchlide reductase (LPOR) and light-independent (dark-operative) Pchlide reductase (DPOR). LPOR is an NADPH-dependent enzyme operating as a key enzyme for the light-dependent greening in angiosperms, and DPOR is a nitrogenase-like enzyme that allows gymnosperms, algae, cyanobacteria and photosynthetic bacteria to produce (bacterio)chlorophylls even in the dark. We will review recent major research progresses on Pchlide reductases, especially, crystallographic structure and proposed reaction mechanism of DPOR. Differential operation and evolutionary implications of these enzymes are also discussed.
