5FIH: Saccharomyces Cerevisiae Gas2p (e176q Mutant) In Complex With Laminaritetraose And Laminaripentaose

Citation:
Abstract
The conversion of glycoside hydrolases (GHs) into transglycosylases (TGs), i.e., from enzymes that hydrolyze carbohydrates to enzymes that synthesize them, represents a promising solution for the large-scale synthesis of complex carbohydrates for biotechnological purposes. However, the lack of knowledge about the molecular details of transglycosylation hampers the rational design of TGs. Here we present the first crystallographic structure of a natural glycosyl-enzyme intermediate (GEI) of Saccharomyces cerevisiae Gas2 in complex with an acceptor substrate and demonstrate, by means of quantum mechanics/molecular mechanics metadynamics simulations, that it is tuned for transglycosylation (DeltaG() = 12 kcal/mol). The 2-OH...nucleophile interaction is found to be essential for catalysis: its removal raises the free energy barrier significantly (11 and 16 kcal/mol for glycosylation and transglycosylation, respectively) and alters the conformational itinerary of the substrate (from (4)C1 --> [(4)E]() --> (1,4)B/(4)E to (4)C1 --> [(4)H3]() --> (4)C1). Our results suggest that changes in the interactions involving the 2-position could have an impact on the transglycosylation activity of several GHs.
PDB ID: 5FIHDownload
MMDB ID: 136612
PDB Deposition Date: 2015/9/25
Updated in MMDB: 2016/04
Experimental Method:
x-ray diffraction
Resolution: 1.8  Å
Source Organism:
Similar Structures:
Biological Unit for 5FIH: monomeric; determined by software (PISA)
Molecular Components in 5FIH
Label Count Molecule
Protein (1 molecule)
1
1,3-beta-glucanosyltransferase
Molecule annotation
Chemicals (9 molecules)
1
2
2
7
* Click molecule labels to explore molecular sequence information.

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