Dataset Information

Structural Insights into the Carbohydrate Binding Ability of an ?-(1?2) Branching Sucrase from Glycoside Hydrolase Family 70.

ABSTRACT: The ?-(1?2) branching sucrase ?N123-GBD-CD2 is a transglucosylase belonging to glycoside hydrolase family 70 (GH70) that catalyzes the transfer ofd-glucosyl units from sucroseto dextrans or gluco-oligosaccharides via the formation of ?-(1?2) glucosidic linkages. The first structures of ?N123-GBD-CD2 in complex withd-glucose, isomaltosyl, or isomaltotriosyl residues were solved. The glucose complex revealed three glucose-binding sites in the catalytic gorge and six additional binding sites at the surface of domains B, IV, and V. Soaking with isomaltotriose or gluco-oligosaccharides led to structures in which isomaltosyl or isomaltotriosyl residues were found in glucan binding pockets located in domain V. One aromatic residue is systematically identified at the bottom of these pockets in stacking interaction with one glucosyl moiety. The carbohydrate is also maintained by a network of hydrogen bonds and van der Waals interactions. The sequence of these binding pockets is conserved and repeatedly present in domain V of several GH70 glucansucrases known to bind ?-glucans. These findings provide the first structural evidence of the molecular interaction occurring between isomalto-oligosaccharides and domain V of the GH70 enzymes.

SUBMITTER: Brison Y

PROVIDER: S-EPMC4817182 | biostudies-literature | 2016 Apr

REPOSITORIES: biostudies-literature

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Structural Insights into the Carbohydrate Binding Ability of an α-(1→2) Branching Sucrase from Glycoside Hydrolase Family 70.

Brison Yoann Y Malbert Yannick Y Czaplicki Georges G Mourey Lionel L Remaud-Simeon Magali M Tranier Samuel S

The Journal of biological chemistry 20160210 14

The α-(1→2) branching sucrase ΔN123-GBD-CD2 is a transglucosylase belonging to glycoside hydrolase family 70 (GH70) that catalyzes the transfer ofd-glucosyl units from sucroseto dextrans or gluco-oligosaccharides via the formation of α-(1→2) glucosidic linkages. The first structures of ΔN123-GBD-CD2 in complex withd-glucose, isomaltosyl, or isomaltotriosyl residues were solved. The glucose complex revealed three glucose-binding sites in the catalytic gorge and six additional binding sites at the ...[more]

PMID: 26865636

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Project description:Among ?-transglucosylases from Glycoside-Hydrolase family 70, the ?N123-GB-CD2 enzyme derived from the bifunctional DSR-E from L. citreum NRRL B-1299 is particularly interesting as it was the first described engineered Branching Sucrase, not able to elongate glucan polymers from sucrose substrate. The previously reported overall structural organization of this multi-domain enzyme is an intricate U-shape fold conserved among GH70 enzymes which showed a certain conformational variability of the so-called domain V, assumed to play a role in the control of product structures, in available X-ray structures. Understanding the role of functional dynamics on enzyme reaction and substrate recognition is of utmost interest although it remains a challenge for biophysical methods. By combining long molecular dynamics simulation (1?s) and multiple analyses (NMA, PCA, Morelet Continuous Wavelet Transform and Cross Correlations Dynamics), we investigated here the dynamics of ?N123-GB-CD2 alone and in interaction with sucrose substrate. Overall, our results provide the detailed picture at atomic level of the hierarchy of motions occurring along different timescales and how they are correlated, in agreement with experimental structural data. In particular, detailed analysis of the different structural domains revealed cooperative dynamic behaviors such as twisting, bending and wobbling through anti- and correlated motions, and also two structural hinge regions, of which one was unreported. Several highly flexible loops surrounding the catalytic pocket were also highlighted, suggesting a potential role in the acceptor promiscuity of ?N123-GBD-CD2. Normal modes and essential dynamics underlined an interesting two-fold dynamic of the catalytic domain A, pivoting about an axis splitting the catalytic gorge in two parts. The comparison of the conformational free energy landscapes using principal component analysis of the enzyme in absence or in presence of sucrose, also revealed a more harmonic basin when sucrose is bound with a shift population of the bending mode, consistent with the substrate binding event.

Dataset Information

Structural Insights into the Carbohydrate Binding Ability of an ?-(1?2) Branching Sucrase from Glycoside Hydrolase Family 70.

Publications

Structural Insights into the Carbohydrate Binding Ability of an α-(1→2) Branching Sucrase from Glycoside Hydrolase Family 70.

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