A single amino acid substitution changes the substrate specificity of quinoprotein glucose dehydrogenase in Gluconobacter oxydans.
Gluconobacter oxydans contains pyrroloquinoline quinone-dependent glucose dehydrogenase (GDH). Two isogenic G. oxydans strains, P1 and P2, which differ in their substrate specificity with respect to oxidation of sugars have been analysed. P1 can oxidize only D-glucose, whereas P2 is also capable of the oxidation of the disaccharide maltose. To investigate the nature of this maltose-oxidizing property we cloned the gene encoding GDH from P2. Expression of P2 gdh in P1 enables the latter strain to oxidize maltose, indicating that a mutation in the P2 gdh gene is responsible for the change in substrate specificity. This mutation could be ascribed to a 1 bp substitution resulting in the replacement of His 787 by Asn.
Cleton-Jansen
A M
AM
Laboratory of Molecular Genetics, University of Leiden, The Netherlands.
Dekker
S
S
van de Putte
P
P
Goosen
N
N
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000235:genetics*; D010582:Bacteriophage lambda / Q000235:genetics; D001483:Base Sequence; D003227:Conjugation, Genetic; D004926:Escherichia coli / Q000201:enzymology; D005814:Genes, Viral; D042843:Glucose 1-Dehydrogenase; D005948:Glucose Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008320:Maltose / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009693:Nucleic Acid Hybridization; D010084:Oxidation-Reduction; D010957:Plasmids; D011548:Pseudomonadaceae / Q000201:enzymology*; D013379:Substrate Specificity
D000596:Amino Acids; D008320:Maltose; D005948:Glucose Dehydrogenases; D042843:Glucose 1-Dehydrogenase