An additional glucose dehydrogenase from Sulfolobus solfataricus: fine-tuning of sugar degradation?
Within the SulfoSYS (Sulfolobus Systems Biology) project, the effect of temperature on a metabolic network is investigated at the systems level. Sulfolobus solfataricus utilizes an unusual branched ED (Entner-Doudoroff) pathway for sugar degradation that is promiscuous for glucose and galactose. In the course of metabolic pathway reconstruction, a glucose dehydrogenase isoenzyme (GDH-2, SSO3204) was identified. GDH-2 exhibits high similarity to the previously characterized GDH-1 (SSO3003, 61% amino acid identity), but possesses different enzymatic properties, particularly regarding substrate specificity and catalytic efficiency. In contrast with GDH-1, which exhibits broad substrate specificity for C5 and C6 sugars, GDH-2 is absolutely specific for glucose. The comparison of kinetic parameters suggests that GDH-2 might represent the major player in glucose catabolism via the branched ED pathway, whereas GDH-1 might have a dominant role in galactose degradation via the same pathway as well as in different sugar-degradation pathways.
Faculty of Chemistry, Biofilm Centre, Molecular Enzyme Technology and Biochemistry, University of Duisburg-Essen, and Department of Otorhinolaryngology, University Hospital of Essen, Universitätsstrasse, Building S03 V03 F44, 45117 Essen, Germany.
Patrick
P
Haferkamp
Simone
S
Kutschki
Jenny
J
Treichel
Hatim
H
Hemeda
Karsten
K
Sewczyk
Daniel
D
Hoffmann
Melanie
M
Zaparty
Bettina
B
Siebers
D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D050260:Carbohydrate Metabolism; D005690:Galactose / Q000737:chemistry / Q000378:metabolism; D005947:Glucose / Q000737:chemistry / Q000378:metabolism; D042843:Glucose 1-Dehydrogenase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D013379:Substrate Specificity; D048229:Sulfolobus solfataricus / Q000201:enzymology* / Q000235:genetics
D019843:Archaeal Proteins; D007527:Isoenzymes; D042843:Glucose 1-Dehydrogenase; D005947:Glucose; D005690:Galactose