Figure 3

Active site close-up of PmMOR bound with NADP⁺ and 8-oxogeranial and sequence alignment of PmMOR, CrIS and Dl5ß-POR. (A) NADP⁺ binding residues depicted as sticks. Residues are labeled and hydrogen bonding interactions are depicted as dotted blue lines with the distances between atoms given. The cofactor binding site is formed primarily by the Rossmann fold domain. Residues ILE-206, MET-215 and SER-213 from the helical cap domain help to sequester the cofactor. (B) 8-oxogeranial binding site labeled as per (A). The distance between the reactive hydride and the substrate is 7.1 Å, non-optimum for catalysis. (C) Sequence alignment of P. major multifunctional oxido-reductase (PmMOR), D. lanata 5-ß progesterone oxido-reductase (Dl5ß-POR) and C. roseus iridoid synthase (CrIS). Approximately every tenth position is marked with an asterisk. Putative catalytic residues are highlighted in cyan and active site mutants are highlighted in yellow. The loop region that differs in orientation between PmMOR and CrIS corresponding to residues 349–354 is underlined.