Identification and Characterization of a Novel, Cold-Adapted d-Xylobiose- and d-Xylose-Releasing Endo-β-1,4-xylanase from an Antarctic Soil Bacterium, Duganella sp. PAMC 27433

Endo-β-1,4-xylanase is a key enzyme in the degradation of β-1,4-d-xylan polysaccharides through hydrolysis. A glycoside hydrolase family 10 (GH10) endo-β-1,4-xylanase (XylR) from Duganella sp. PAMC 27433, an Antarctic soil bacterium, was identified and functionally characterized. The XylR gene (1122...

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Bibliographic Details
Published in:Biomolecules
Main Authors: Do Young Kim, Jonghoon Kim, Yung Mi Lee, Jong Suk Lee, Dong-Ha Shin, Bon-Hwan Ku, Kwang-Hee Son, Ho-Yong Park
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2021
Subjects:
Antarctic bacterium
Duganella sp
GH10
cold-adapted
endo-β-1,4-xylanase
Microbiology
QR1-502
Antarctic
Triton
Antarc*
Online Access:https://doi.org/10.3390/biom11050680
https://doaj.org/article/45bad10f0b684d68bdc8c923b0869db4
Description
Summary:Endo-β-1,4-xylanase is a key enzyme in the degradation of β-1,4-d-xylan polysaccharides through hydrolysis. A glycoside hydrolase family 10 (GH10) endo-β-1,4-xylanase (XylR) from Duganella sp. PAMC 27433, an Antarctic soil bacterium, was identified and functionally characterized. The XylR gene (1122-bp) encoded an acidic protein containing a single catalytic GH10 domain that was 86% identical to that of an uncultured bacterium BLR13 endo-β-1,4-xylanase (ACN58881). The recombinant enzyme (rXylR: 42.0 kDa) showed the highest beechwood xylan-degrading activity at pH 5.5 and 40 °C, and displayed 12% of its maximum activity even at 4 °C. rXylR was not only almost completely inhibited by 5 mM N -bromosuccinimide or metal ions (each 1 mM) including Hg 2+ , Ca 2+ , or Cu 2+ but also significantly suppressed by 1 mM Ni 2+ , Zn 2+ , or Fe 2+ . However, its enzyme activity was upregulated (>1.4-fold) in the presence of 0.5% Triton X-100 or Tween 80. The specific activities of rXylR toward beechwood xylan, birchwood xylan, oat spelts xylan, and p -nitrophenyl-β-d-cellobioside were 274.7, 103.2, 35.6, and 365.1 U/mg, respectively. Enzymatic hydrolysis of birchwood xylan and d-xylooligosaccharides yielded d-xylose and d-xylobiose as the end products. The results of the present study suggest that rXylR is a novel cold-adapted d-xylobiose- and d-xylose-releasing endo-β-1,4-xylanase.

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