Characterization and engineering of a novel pyrroloquinoline quinone dependent glucose dehydrogenase from Sorangium cellulosum So ce56.
A novel pyrroloquinoline quinone dependent glucose dehydrogenase like enzyme (PQQ GDH) was isolated from Sorangium cellulosum So ce56. The putative coding region was cloned, over expressed in E. coli and the resulting enzyme was characterized. The recombinant protein has a relative molecular mass of 63 kDa and shows 43% homology to PQQ GDH-B from Acinetobacter calcoaceticus. In the presence of PQQ and CaCl₂ the enzyme has dehydrogenase activity with the substrate glucose as well as with other mono- and disaccharides. The thermal stability and its pH activity profile mark the enzyme as a potential glucose biosensor enzyme. In order to decrease the activity on maltose, which is unwanted for a potential application in biosensors, the protein was rationally modified at three specified positions. The best variant showed a 59% reduction in activity on maltose compared to the wild type enzyme. The catalytic efficiency (k(cat)/K(M)) was reduced fivefold but the specific activity still amounted to 63% of the wild type activity.
Hofer
Michael
M
Institute of Biochemistry, University of Leipzig, Deutscher Platz 5b, 04103 Leipzig, Germany. hofer@uni-leipzig.de
Bönsch
Kathrin
K
Greiner-Stöffele
Thomas
T
Ballschmiter
Meike
M
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005948:Glucose Dehydrogenases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009231:Myxococcales / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D001426:Bacterial Proteins; D005948:Glucose Dehydrogenases; C033955:glucose dehydrogenase (pyrroloquinoline-quinone)