Stereochemistry of the reduction step mediated by recombinant 1-deoxy-D-xylulose 5-phosphate isomeroreductase

[GRAPHICS] The stereochemistry of the 1-deoxy-D-xylulose 5-phosphate (DXP) isomeroredu ctase reduction step has been examined using the recombinant enzyme from Sy nechocystis sp. PCC6803, Using [3-H-2]DXP and [4S-H-2]NADPH, it has been de termined that the C1 pro-S hydrogen in the 2-C-methyl-D-erythritol 4-phosph ate product derives from C3 of DXP, indicating that hydride attack occurs o n the re face of the intermediate aldehyde, The 4S-hydride from NADPH is de livered, assigning this enzyme as a class B dehydrogenase.