An additional glucose dehydrogenase from Sulfolobus solfataricus: fine-tuning of sugar degradation?

Biochem Soc Trans. 2011 Jan;39(1):77-81. doi: 10.1042/BST0390077.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Archaeal Proteins / chemistry
  • Archaeal Proteins / genetics
  • Archaeal Proteins / metabolism*
  • Binding Sites
  • Carbohydrate Metabolism*
  • Galactose / chemistry
  • Galactose / metabolism
  • Glucose / chemistry
  • Glucose / metabolism
  • Glucose 1-Dehydrogenase / chemistry
  • Glucose 1-Dehydrogenase / genetics
  • Glucose 1-Dehydrogenase / metabolism*
  • Isoenzymes / chemistry
  • Isoenzymes / genetics
  • Isoenzymes / metabolism*
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation
  • Substrate Specificity
  • Sulfolobus solfataricus / enzymology*
  • Sulfolobus solfataricus / genetics

Substances

  • Archaeal Proteins
  • Isoenzymes
  • Glucose 1-Dehydrogenase
  • Glucose
  • Galactose