Crystal structures of glycogen-debranching enzyme mutants in complex with oligosaccharides

Debranching is a critical step in the mobilization of the important energy store glycogen. In eukaryotes, including fungi and animals, the highly conserved glycogen-debranching enzyme (GDE) debranches glycogen by a glucanotransferase (GT) reaction followed by a glucosidase (GC) reaction. Previous work indicated that these reactions are catalyzed by two active sites located more than 50   Å apart and provided insights into their catalytic mechanisms and substrate recognition. Here, five crystal structures of GDE in complex with oligosaccharides with 4 – 9 glucose residues are presented. The data suggest that the glycogen main chain plays a critical role in binding to the GT and GC active sites of GDE and that a minimum of five main-chain residues are required for optimal binding.

Source: Acta Crystallographica Section F - October 29, 2021 Category: Biochemistry Authors: Shen, M. Gong, X. Xiang, S. Tags: glycogen-debranching enzymes Candida glabrata research communications Source Type: research