engleski

Computational Investigation of Enzymatic Dehydration of Glycerol

Some bacteria are able to grow under anaerobic conditions, using non-standard carbon sources such as glycerols and diols. Enzymes which catalyze the fermentation of glycerol are coenzyme B12-dependent diol dehydratase (DDH) and B12-dependent glycerol dehydratase (GDH). Coenzyme B12 (5'-deoxyadenosyl-cobalamine) is naturally occurring organometallic copound which contains the unique Co-C sigma bond responsible for radical mechanism of catalysis. Recently, another enzyme which catalyzes the same reaction has been characterizes. However, its action is not dependent of coenzyme B12. In the present work, hybrid quantum mechanical/molecular mechanical (QM/MM) calculations are used to characterize the possible pathways for dehydration of glycerol catalyzed by B12-dependent GDH. The influences of active site amino acid residues are examined, including the protonation states of residue His143. The results are compared to those obtained earlier for B12-independent glycerol dehydratase.

enzymatic dehydration of alcohols; reaction mechanism; QM/MM

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