A plasmid borne, functionally novel glycoside hydrolase family 30 subfamily 8 endoxylanase from solventogenic Clostridium
- USDA Forest Service, Madison, WI (United States). Institute for Microbial and Biochemical Technology, Forest Products Laboratory
- University of Maryland School of Pharmacy, Baltimore, MD (United States). Department of Pharmaceutical Sciences
- University of Maryland School of Medicine, Rockville, MD (United States). Institute for Bioscience and Biotechnology Research, Department of Biochemistry and Molecular Biology
- Winthrop University, Rock Hill, SC (United States). Department of Chemistry, Physics and Geology
Glycoside hydrolase family 30 subfamily 8 (GH30-8) β-1,4-endoxylanases are known for their appendage-dependent function requiring recognition of an α-1,2-linked glucuronic acid (GlcA) common to glucuronoxylans for hydrolysis. Structural studies have indicated that the GlcA moiety of glucuronoxylans is coordinated through six hydrogen bonds and a salt bridge. These GlcA-dependent endoxylanases do not have significant activity on xylans that do not bear GlcA substitutions such as unsubstituted linear xylooligosaccharides or cereal bran arabinoxylans. In the present study, we present the structural and biochemical characteristics of xylanase 30A from Clostridium acetobutylicum (CaXyn30A) which was originally selected for study due to predicted structural differences within the GlcA coordination loops. Amino acid sequence comparisons indicated that this Gram-positive-derived GH30-8 more closely resembles Gram-negative derived forms of these endoxylanases: a hypothesis borne out in the developed crystallographic structure model of the CaXyn30A catalytic domain (CaXyn30A-CD). CaXyn30A-CD hydrolyzes xylans to linear and substituted oligoxylosides showing the greatest rate with the highly arabinofuranose (Araf)-substituted cereal arabinoxylans. CaXyn30A-CD hydrolyzes xylooligosaccharides larger than xylotriose and shows an increased relative rate of hydrolysis for xylooligosaccharides containing α-1,2-linked arabinofuranose substitutions. Biochemical analysis confirms that CaXyn30A benefits from five xylose-binding subsites which extend from the -3 subsite to the +2 subsite of the binding cleft. These studies indicate that CaXyn30A is a GlcA-independent endoxylanase that may have evolved for the preferential recognition of α-1,2-Araf substitutions on xylan chains.
- Research Organization:
- SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); USDA; US Forest Service; National Center for Research Resources (NCRR); USDOE Office of Science (SC), Biological and Environmental Research (BER); National Institutes of Health (NIH); National Institute of General Medical Sciences (NIGMS)
- Grant/Contract Number:
- AC02-76SF00515; 5 P20 RR016461
- OSTI ID:
- 1624988
- Journal Information:
- Biochemical Journal, Vol. 475, Issue 9; ISSN 0264-6021
- Publisher:
- Biochemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
A novel fungal GH30 xylanase with xylobiohydrolase auxiliary activity
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journal | May 2019 |
Peptide-based functional annotation of carbohydrate-active enzymes by conserved unique peptide patterns (CUPP)
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journal | April 2019 |
CaXyn30B from the solventogenic bacterium Clostridium acetobutylicum is a glucuronic acid-dependent endoxylanase
|
journal | June 2020 |
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