Identification of acceptor substrate binding subsites +2 +3 in the amylomaltase from Thermus thermophilus HB8

Glycoside hydrolase family 77 (GH77) belongs to the α-amylase superfamily (Clan H) together with GH13 and GH70. GH77 enzymes are amylomaltases or 4-α-glucanotransferases, involved in maltose metabolism in microorganisms and in starch biosynthesis in plants. Here we characterized the amylomaltase from the hyperthermophilic bacterium Thermus...

Three-way stabilization of the covalent intermediate in amylomaltase, an alpha-like transglycosylase

Amylomaltases are glycosyl hydrolases belonging to glycoside hydrolase family 77 that are capable of the synthesis of large cyclic glucans and the disproportionation of oligosaccharides. Using protein crystallography, we have generated a flip book movie of the amylomaltase catalytic cycle in atomic detail. The structures include a covalent...

Single amino acid residue changes in subsite - 1 of inulosucrase from Lactobacillus reuteri 121 strongly influence the size of products synthesized

Bacterial fructansucrase enzymes belong to glycoside hydrolase family 68 and catalyze transglycosylation reactions with sucrose, resulting in the synthesis of fructooligosaccharides and/or a fructan polymer. Significant differences in fructansucrase enzyme product specificities can be observed, i.e. in the type of polymer (levan or inulin)...

A novel thermoreversible gelling product made by enzymatic modification of starch

Amylomaltases or D-enzyme (4-α-glucanotransferases; E.C. 2.4.1.25) are carbohydrate-active enzymes that catalyze the transfer of glucan units from one α-glucan to another in a disproportionation reaction. These enzymes are involved in starch metabolism in plants or maltose/glycogen metabolism in many microorganisms. The amylomaltase of the...

Amylomaltase of Pyrobaculum aerophilum IM2 produces thermoreversible starch gels

Amylomaltases are 4-alpha-glucanotransferases (EC 2.4.1.25) of glycoside hydrolase family 77 that transfer alpha-1,4-linked glucans to another acceptor, which can be the 4-OH group of an alpha-1,4-linked glucan or glucose. The amylomaltase-encoding gene (PAE1209) from the hyperthermophilic archaeon Pyrobaculum aerophilum IM2 was cloned and...

Exploring and exploiting starch-modifying amylomaltases from thermophiles