Mechanistic investigation of B12-independent glycerol dehydratase and its activating enzyme GD-AE.

Yaoyang Li, Yadi Yao, Lu Yu, Changlin Tian, Min Dong

Chemical communications (Cambridge, England) 2022 Feb 22

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B12-Independent glycerol dehydratase (GD) is a glycyl radical enzyme in the biotransformation of glycerol to 1,3-propanediol. GD requires the activating enzyme GD-AE to initiate the radical reaction. GD-AE belongs to the radical S-adenosyl-L-methionine (SAM) enzyme superfamily. However, a previous study showed that GD-AE cleaves SAM unconventionally to generate 5'-deoxy-5'-methylthioadenosine. Herein, we show that GD-AE actually cleaves SAM to form 5'-deoxyadenosine, similar to other radical SAM enzymes. Furthermore, with the synthesized glycerol analogue 2-deoxy-2-fluoroglycerol, we demonstrate that B12-independent GD catalyzes the glycerol dehydration reaction by direct elimination of the C-2 hydroxyl group of a ketyl radical rather than 1,2-OH migration.

Citation

Yaoyang Li, Yadi Yao, Lu Yu, Changlin Tian, Min Dong. Mechanistic investigation of B12-independent glycerol dehydratase and its activating enzyme GD-AE. Chemical communications (Cambridge, England). 2022 Feb 22;58(16):2738-2741