Glucose-fructose oxidoreductase

 

Glucose-fructose oxidoreductase catalyses both the reduction of fructose and the oxidation of glucose simultaneously, reactions which allow certain bacteria to tolerate high sugar concentrations. The gluconolactone produced is subsequently converted to ethanol whilst the sorbital is not metabolised further. The biotechnological interest in an efficient microbial production of ethanol production had lead to a huge interest in enzymes such as these. It is located in the periplasmic space of the bacterial cells where its biological function is to protect the bacterium from osmotic stress caused by high sugar concentrations.

 

Reference Protein and Structure

Sequence
Q07982 UniProt (1.1.99.28) IPR008354 (Sequence Homologues) (PDB Homologues)
Biological species
Zymomonas mobilis subsp. mobilis ZM4 = ATCC 31821 (Bacteria) Uniprot
PDB
1ofg - GLUCOSE-FRUCTOSE OXIDOREDUCTASE (2.7 Å) PDBe PDBsum 1ofg
Catalytic CATH Domains
3.30.360.10 CATHdb 3.40.50.720 CATHdb (see all for 1ofg)
Cofactors
Nadp zwitterion (1)
Click To Show Structure

Enzyme Reaction (EC:1.1.99.28)

D-fructofuranose
CHEBI:37721ChEBI
+
D-glucopyranose
CHEBI:4167ChEBI
→
D-glucono-1,5-lactone
CHEBI:16217ChEBI
+
D-glucitol
CHEBI:17924ChEBI

Enzyme Mechanism

Introduction

Catalysis is achieved by a ping pong mechanism where one of its substrates binds and forms a product that dissociates before the second product binds. The residues involved are yet to be identified conclusively but there is some speculation. Tyr217 is the most likely residue to act as a proton donor/acceptor. Lys129 is thought to hydrogen bond to the adjacent Tyr217 and facilitate proton transfer.

Catalytic Residues Roles

UniProt PDB* (1ofg)
Lys181 Lys129A Helps stabilise the reactive intermediates and transition states formed during the course of the reaction. electrostatic stabiliser
Tyr269 Tyr217A Acts as a general acid/base. proton shuttle (general acid/base)
*PDB label guide - RESx(y)B(C) - RES: Residue Name; x: Residue ID in PDB file; y: Residue ID in PDB sequence if different from PDB file; B: PDB Chain; C: Biological Assembly Chain if different from PDB. If label is "Not Found" it means this residue is not found in the reference PDB.

Chemical Components

References

  1. Nurizzo D et al. (2001), Biochemistry, 40, 13857-13867. Crystal structures of the precursor form of glucose-fructose oxidoreductase from Zymomonas mobilis and its complexes with bound ligands. PMID:11705375.
  2. Taberman H et al. (2016), Protein Sci, 25, 778-786. Structural and functional features of the NAD(P) dependent Gfo/Idh/MocA protein family oxidoreductases. DOI:10.1002/pro.2877. PMID:26749496.
  3. Lott JS et al. (2000), J Mol Biol, 304, 575-584. Crystal structure of a truncated mutant of glucose-fructose oxidoreductase shows that an N-terminal arm controls tetramer formation. DOI:10.1006/jmbi.2000.4245. PMID:11099381.
  4. Kingston RL et al. (1996), Structure, 4, 1413-1428. The structure of glucose-fructose oxidoreductase from Zymomonas mobilis: an osmoprotective periplasmic enzyme containing non-dissociable NADP. DOI:10.1016/s0969-2126(96)00149-9. PMID:8994968.

Step 1.

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Catalytic Residues Roles

Residue Roles
Tyr217A proton shuttle (general acid/base)
Lys129A electrostatic stabiliser

Chemical Components

Step 1.

Contributors

Alex Gutteridge, Craig Porter, Gemma L. Holliday