xylA cloning and sequencing and biochemical characterization of xylose isomerase from Thermotoga neapolitana

The xylA gene of Thermotoga neapolitana was cloned and expressed in Escherichia coli to study the structure and properties of the enzyme it codes for. Xylose isomerase is most active at 95 degrees centigrade, is stable over a wide range of pH and belongs to the xylose isomerase family II. The thermostability of this enzyme is probably because it has less glutamine and asparagine residues which are denatured at high temperatures. However, the properties of this enzyme are different from those of the enzyme produced by the closely related species Thermotoga maritima.