Biochemical characterization and sequence analysis

Authors: HyunWoo Oh SunYeon Heo Do Young Kim DooSang Park Kyung Sook Bae HoYong Park

Publish Date: 2007/11/20

Volume: 93, Issue: 4, Pages: 437-442

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Abstract

An exosymbiotic bacterium capable of hydrolyzing xylan was isolated from the gut of the mole cricket Gryllotalpa orientalis and identified as Cellulosimicrobium sp HY12 The xylanase XylACspHY12 of this organism bound tightly to both DEAE and mono Q resins and its molecular mass M r was about 390 kDa The highest xylanase activity was observed at pH 60 and 60°C The enzyme was greatly suppressed by Ca2+ Cu2+ Co2+ and Fe2+ ions but not by Mg2+ and Mn2+ Although XylACspHY12 was capable of hydrolyzing various types of xylosic compounds it could not decompose carboxymethyl cellulose or xylobiose The xylA CspHY12 gene consisted of an 1188 bp open reading frame that encoded a polypeptide of 395 amino acids with a deduced molecular mass of 42925 Da The domain structure of XylACspHY12 was most similar to those of the glycoside hydrolase GH family 10 endoxylanases However its sequence identity with any of the enzymes in this family was below 52 The results of this study suggest that the XylACspHY12 is a new cellulasefree endoβ14xylanase with some properties that are distinct from those of GH family 10

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