formation of a branched isomalto/malto-polysaccharide from branched malto-oligosaccharides
Comment
The enzyme, discovered in several bacterial species, is similar to EC 2.4.1.395, reuteransucrase, yet is not able to act on sucrose. The enzyme, which belongs to the glycoside hydrolase 70 (GH70) family, possesses both hydrolase and transglycosylase activities, cleaving endo alpha(1->4) linkages from the non-reducing end of maltooligosaccharides and adding the resulting oligosaccharides to the non-reducing end of alpha-D-glucan chains that terminate with a residue linked by an alpha-(1->4) linkage, forming an alpha(1->6) linkage. The enzyme is not able to form successive alpha(1->6) linkages. Unlike EC 2.4.1.394, 4,6-alpha-glucanotransferase (linear substrates/linear products), which can only act on linear substrates, this enzyme is able to act on both linear and branched substrates, and can form the branched reuteran type of alpha-glucan.
Gangoiti J, van Leeuwen SS, Vafiadi C, Dijkhuizen L.
Title
The Gram-negative bacterium Azotobacter chroococcum NCIMB 8003 employs a new glycoside hydrolase family 70 4,6-alpha-glucanotransferase enzyme (GtfD) to synthesize a reuteran like polymer from maltodextrins and starch.
Pijning T, Gangoiti J, Te Poele EM, Borner T, Dijkhuizen L.
Title
Insights into Broad-Specificity Starch Modification from the Crystal Structure of Limosilactobacillus Reuteri NCC 2613 4,6-alpha-Glucanotransferase GtfB.
