Structure and function of glucose dehydrogenase from Escherichia coli
Structure and function of glucose dehydrogenase from Escherichia coli
Glucose dehydrogenase (GDH) is a membrane bound PQQ- containing quinoprotein which catalyses the oxidation of D-glucose to gluconolactone. In E. coli under growth conditions used so far, the enzyme is produced as the apo-form in the absence of added PQQ. This is due to the lack of PQQ production. The apo-enzyme can be reconstituted to the active holo-form by addition of PQQ and a divalent cation.
Other PQQ-containing dehydrogenases include those that oxidase alcohol and methanol. Methanol dehydrogenase (MDH) of Methylobacterium extorquens is a soluble quinoprotein, whose X-ray structure (at 1.94Å) has recently been published. It has an α2β2 tetrameric structure; the α-subunit which contains the active site is a super-barrel having an 8-fold radial symmetry stabilised by a novel tryptophan-docking motif. The PQQ is held in place in the active site by a coplanar tryptophan and by a novel disulphide ring structure. Three types of alcohol dehydrogenase (ADH) have been identified. Sequence homology indicated that part of GDH and ADH may have equivalent super-barrel structures to MDH. In this work the sequences of the relevant parts of a type III ADH from Acetobacter aceti and GDH from E. coli were modelled onto the X-ray structure of MDH from Methylobacterium extorquens. Also the sequence of a proposed type I ADH from Azoarcus sp. BH72 was modelled onto the MDH structure. This work supported the suggestion that the enzymes have a similar structure, because many of the structural features found in MDH were conserved in the model ADH and GDH structures.
Enzyme characterisation of the wild-type and mutant enzymes was carried out. This included substrate specificity, inhibitor studies and factors effecting reconstitution of the apo-enzyme.
Sequence comparisons indicated that the membrane bound GDH was comprised of a membrane anchor and a periplasmic super-barrel domain similar in structure to the α-subunit of MDH.
University of Southampton
1998
Cozier, Gyles Eldred
(1998)
Structure and function of glucose dehydrogenase from Escherichia coli.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Glucose dehydrogenase (GDH) is a membrane bound PQQ- containing quinoprotein which catalyses the oxidation of D-glucose to gluconolactone. In E. coli under growth conditions used so far, the enzyme is produced as the apo-form in the absence of added PQQ. This is due to the lack of PQQ production. The apo-enzyme can be reconstituted to the active holo-form by addition of PQQ and a divalent cation.
Other PQQ-containing dehydrogenases include those that oxidase alcohol and methanol. Methanol dehydrogenase (MDH) of Methylobacterium extorquens is a soluble quinoprotein, whose X-ray structure (at 1.94Å) has recently been published. It has an α2β2 tetrameric structure; the α-subunit which contains the active site is a super-barrel having an 8-fold radial symmetry stabilised by a novel tryptophan-docking motif. The PQQ is held in place in the active site by a coplanar tryptophan and by a novel disulphide ring structure. Three types of alcohol dehydrogenase (ADH) have been identified. Sequence homology indicated that part of GDH and ADH may have equivalent super-barrel structures to MDH. In this work the sequences of the relevant parts of a type III ADH from Acetobacter aceti and GDH from E. coli were modelled onto the X-ray structure of MDH from Methylobacterium extorquens. Also the sequence of a proposed type I ADH from Azoarcus sp. BH72 was modelled onto the MDH structure. This work supported the suggestion that the enzymes have a similar structure, because many of the structural features found in MDH were conserved in the model ADH and GDH structures.
Enzyme characterisation of the wild-type and mutant enzymes was carried out. This included substrate specificity, inhibitor studies and factors effecting reconstitution of the apo-enzyme.
Sequence comparisons indicated that the membrane bound GDH was comprised of a membrane anchor and a periplasmic super-barrel domain similar in structure to the α-subunit of MDH.
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Published date: 1998
Identifiers
Local EPrints ID: 463211
URI: http://eprints.soton.ac.uk/id/eprint/463211
PURE UUID: ecb801fd-a32c-4107-9667-d4c148c497c3
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Date deposited: 04 Jul 2022 20:47
Last modified: 04 Jul 2022 20:47
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Author:
Gyles Eldred Cozier
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