Fig. 9
From: Discovery of novel geranylgeranyl reductases and characterization of their substrate promiscuity
(Left) overlaid prediction of modeled protein structures of proteins (Sa, cyan; Pf, tan; Af, fuschia; Mi, green; Tn, red; Ta, gray; Sc, magenta; Ma, orange) with demonstrated GGR activity using SaGGR (PDB: 4opd) as a template. (Middle) overlaid alignment of protein active sites of residues within 10 Å of either the FAD isoalloxazine ring or GGPP substrate. The conservation of the active site cysteine found in all GGRs (cf. Fig. 8) are found in proper position to modulate the redox properties of the cofactor. (Right) examination of the ScGGR active site containing the divergent REG catalytic motif relative to the GGG motif found in archaeal GGRs. Arg293 and Glu294 of ScGGR make critical intradomain hydrogen bonding interactions to accommodate the GGPP binding site