Crystallization studies of a low molecular weight xylanase from scytalidium thermophilum

Abstract

Xylanases are hydrolytic enzymes which lately attracted increasing attention due to their broad use in different industrial processes. Scytalidium thermophilum xylanase was previously shown by our research group to be a potential candidate for the industry. Therefore, the aim of this study was to optimize the crystal growth conditions of xylanase for further structural studies. Initial crystallization conditions were screened by using commercial kits with sitting drop vapor diffusion method. Consequently, optimization studies were carried out by changing the xylanase concentration, pH, reservoir solution to xylanase ratio in the drop and precipitant concentration. As a result of the study, the best xylanase crystal was obtained from the solution containing 1.8 M ammonium citrate dibasic, 0.1 M sodium acetate trihydrate at pH 4.6 and 2 mg/ml enzyme at 18°C with streak seeding. The largest and well shaped single xylanase crystal at a size of 320 µm with a light-brown color, which has the potential as a starting point of further X-ray diffraction analysis and structural studies, was obtained.