Crystal Structure of <i>Bacillus subtilis</i> α-Amylase in Complex with Acarbose

Abstract

The crystal structure of Bacillus subtilis alpha-amylase, in complex with the pseudotetrasaccharide inhibitor acarbose, revealed an hexasaccharide in the active site as a result of transglycosylation. After comparison with the known structure of the catalytic-site mutant complexed with the native substrate maltopentaose, it is suggested that the present structure represents a mimic intermediate in the initial stage of the catalytic process.