Characterization of glucose transport in the hyperthermophilic Archaeon Sulfolobus solfataricus

AbstractSulfolobus solfataricus is a hyperthermophilic Archaeon growing at 80°C, pH 3. The glucose transport system of this organism has been characterised kinetically at this temperature and pH using 2-deoxy-d-glucose: the sugar analogue is transported into the cells with a Km=1.8±0.3μM and a Vmax=3.6±0.1 nmol min−1 (mg protein)−1, with an intracellular accumulation of up to 200-fold over the extracellular concentration. Transport was significantly reduced at pH 5. Inhibition of 2-deoxy-d-glucose transport was investigated using a variety of sugars and sugar analogues; d-glucose, d-galactose and d-mannose showed the highest affinity for the transporter, with d-glucose possessing a Ki=120±20 nM