Purification and Characterization of a Family G/11 β-Xylanase from Streptomyces olivaceoviridis E-86

Abstract

A β-xylanase (GXYN) was purified from the culture filtrate of Streptomyces olivaceoviridis E-86 by successive chromatography on DE-52, CM-Sepharose and Superose 12. The molecular mass of the xylanase was estimated to be 23 kDa, indicating that the enzyme consists of a catalytic domain only. The enzyme dis- played an optimum pH of 6, a temperature optimum of 60°C, a pH stability range from 2 to 11 and thermal stability up to 40°C. The N-terminal amino acid sequence of GXYN was A-T-V-I-T-T-N-Q-T-G-T-N-N-G-I-Y-Y-S-F-W-, and sharing a high degree of similarity with the N-terminal sequence of xylanases B and C from Streptomyces lividans, indicating GXYN belongs to family G/11 of glycoside hydrolases. GXYN was inferior to xylanase B from Streptomyces lividans in the hydrolysis of insoluble xylan because of its lack of a xylan binding domain. © 2000 by Japan Society for Bioscience, Biotechnology, and Agrochemistry.