Identification of the sequence motif of glycoside hydrolase 13 family members

A bioinformatics analysis of sequences of enzymes of the glycoside hydrolase (GH) 13 family members such as alpha-amylase, cyclodextrin glycosyltransferase (CGTase), branching enzyme and cyclomaltodextrinase has been carried out in order to find out the sequence motifs that govern the reactions specificities of these enzymes by using hidden Markov model (HMM) profile. This analysis suggests the existence of such sequence motifs and residues of these motifs constituting the -1 to +3 catalytic subsites of the enzyme. Hence, by introducing mutations in the residues of these four subsites, one can change the reaction specificities of the enzymes. In general it has been observed that alpha - amylase sequence motif have low sequence conservation than rest of the motifs of the GH13 family members.