Biochemical characterization and sequence analysis of a xylanase produced by an exo-symbiotic bacterium of Gryllotalpa orientalis, Cellulosimicrobium sp. HY-12

Abstract

An exo-symbiotic bacterium capable of hydrolyzing xylan was isolated from the gut of the mole cricket, Gryllotalpa orientalis, and identified as Cellulosimicrobium sp. HY-12. The xylanase (XylA( CspHY-12)) of this organism bound tightly to both DEAE and mono Q resins, and its molecular mass (M(r)) was about 39.0 kDa. The highest xylanase activity was observed at pH 6.0 and 60 degrees C. The enzyme was greatly suppressed by Ca(2+), Cu(2+), Co(2+), and Fe(2+) ions but not by Mg(2+) and Mn(2+). Although XylA( CspHY-12) was capable of hydrolyzing various types of xylosic compounds, it could not decompose carboxymethyl cellulose or xylobiose. The xylA (CspHY-12 ) gene consisted of an 1,188 bp open reading frame that encoded a polypeptide of 395 amino acids with a deduced molecular mass of 42,925 Da. The domain structure of XylA( CspHY-12) 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 XylA( CspHY-12) is a new cellulase-free endo-beta-1,4-xylanase with some properties that are distinct from those of GH family 10.

Novel GH10 Xylanase, with a Fibronectin Type 3 Domain, from Cellulosimicrobium sp. Strain HY-13, a Bacterium in the Gut of Eisenia fetida

“…The maximum catalytic activity of rXylK1 toward birch wood xylan was observed at pH 6.0 and 55°C, and it maintained over 80% of its highest activity at a relatively broad pH range of 5.0 to 9.0 during the reaction period of 15 min. These high activities of rXylK1 in alkaline pH ranges suggest that it is a peculiar enzyme that can be distinguished from xylanases of other invertebrate-symbiotic microorganisms, which showed weak hydrolytic activities toward xylan at the same alkaline pHs (4,11,15). At 55°C, the half-life of rXylK1 was approximately 10 min, which indicates that it is a typical mesophilic enzyme.…”

“…However, no X 1 was detected as the hydrolysis product of X 2 , X 3 , or X 4 . The ability of rXylK1 to catalyze the synthesis of longer xylooligosaccharides from X 3 or X 4 was of interest because microbial xylanases generally produced shorter xylooligosaccharides, such as X 2 and/or X 3 , from the same substrates (2,15). Additionally, rXylK1 primar- on April 27, 2019 by guest http://aem.asm.org/ ily degraded birch wood xylan to X 2 (65.1%) and X 3 (29.5%) together with small amounts of X 4 (5.4%) when the enzyme reaction was conducted for 6 h at 37°C.…”

Cloning of a New Xylanase Gene from Streptomyces sp. TN119 Using a Modified Thermal Asymmetric Interlaced-PCR Specific for GC-Rich Genes and Biochemical Characterization

“…HY-12 (ABX88978) showed the same optimum pH, optimum temperature, and thermostability with that of r-XynA119, but retained over 80% of its original activity in a narrower pH range of 4.5-7.0 and significantly inactivated at pH over 8.0. XylA CspHY-12 was also sensitive to Ca 2+ , Cu 2+ , Co 2+ , and Fe 2+ at the concentration of 10 mM [37]. The xylanase XylA from T. alba ULJB1 (CAB02654) had similar optimum pH to r-XynA119, but showed worse pH stability and higher optimum temperature (80°C).…”

“…2). The significant property difference between these clusters is that xylanases in cluster 1 showed higher optimum pH (pH 7.0-7.8) [31,35,36] than that in cluster 2 (pH 6.0-6.5) [33,37]. Most members in cluster 2 are putative xylanases which are analyzed based on conceptual translation of genomes, and characterization of GH 10 xylanases from Streptomyces in cluster 2 has not been reported so far.…”

A novel xylanase with tolerance to ethanol, salt, protease, SDS, heat, and alkali from actinomycete Lechevalieria sp. HJ3

“…TN119 (ACR61563) [36], 47.2 % with XylA CspHY-12 from Cellulosimicrobium sp. HY-12 (ABX88978) [25], and 46.1 % with XylA from Thermomonospora alba ULJB1 (CAB02654) [4]. Furthermore, XynAHJ3 showed 46.2 % identity with the GH 10 endoxylanase XYNAM6 from Streptomyces megasporus DSM 41476 (ADE37527) [27], 44.0 % with the GH 10 endoxylanase XynAS9 from Streptomyces sp.…”