7P43

Structure of CgGBE in complex with maltotriose

Summary for 7P43

• Entry DOI: 10.2210/pdb7p43/pdb
• Related PRD ID: PRD_900009
• Descriptor: 1,4-alpha-glucan-branching enzyme, alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose (3 entities in total)
• Functional Keywords: glycogen branching enzyme, carbohydrate
• Biological source: Candida glabrata (strain ATCC 2001 / CBS 138 / JCM 3761 / NBRC 0622 / NRRL Y-65) (Yeast, Torulopsis glabrata)
• Total number of polymer chains: 2
• Total formula weight: 163296.59

Authors

Ballut, L.,Conchou, L.,Violot, S.,Galisson, F.,Aghajari, N. (deposition date: 2021-07-09, release date: 2022-07-27, Last modification date: 2024-01-31)

Primary citation

Conchou, L.,Martin, J.,Goncalves, I.R.,Galisson, F.,Violot, S.,Guilliere, F.,Aghajari, N.,Ballut, L.
The Candida glabrata glycogen branching enzyme structure reveals unique features of branching enzymes of the Saccharomycetaceae phylum.
Glycobiology, 32:343-355, 2022

PubMed Abstract: Branching enzymes (BE) are responsible for the formation of branching points at the 1,6 position in glycogen and starch, by catalyzing the cleavage of α-1,4-linkages and the subsequent transfer by introducing α-1,6-linked glucose branched points. BEs are found in the large GH13 family, eukaryotic BEs being mainly classified in the GH13_8 subfamily, GH13_9 grouping almost exclusively prokaryotic enzymes. With the aim of contributing to the understanding of the mode of recognition and action of the enzymes belonging to GH13_8, and to the understanding of features distinguishing these enzymes from those belonging to subfamily 13_9, we solved the crystal structure of the glycogen branching enzyme (GBE) from the yeast Candida glabrata, CgGBE, in ligand-free forms and in complex with a maltotriose. The structures revealed the presence of a domain already observed in Homo sapiens and Oryza sativa BEs that we named α-helical N-terminal domain, in addition to the three conserved domains found in BE. We confirmed by phylogenetic analysis that this α-helical N-terminal domain is always present in the GH13_8 enzymes suggesting that it could actually present a signature for this subfamily. We identified two binding sites in the α-helical N-terminal domain and in the carbohydrate binding module 48 (CBM48), respectively, which show a unique structural organization only present in the Saccharomycotina phylum. Our structural and phylogenetic investigation provides new insight into the structural characterization of GH13_8 GBE revealing that unique structural features only present in the Saccharomycotina phylum thereby conferring original properties to this group of enzymes.

PubMed: 34939121
DOI: 10.1093/glycob/cwab110

Experimental method

X-RAY DIFFRACTION (1.93 Å)