Two New Xylanases with Different Substrate Specificities from the Human Gut Bacterium Bacteroides intestinalis DSM 17393
KAUST DepartmentBiological and Environmental Sciences and Engineering (BESE) Division
Environmental Science and Engineering Program
Water Desalination and Reuse Research Center (WDRC)
Online Publication Date2014-01-24
Print Publication Date2014-04-01
Permanent link to this recordhttp://hdl.handle.net/10754/554126
MetadataShow full item record
AbstractXylan is an abundant plant cell wall polysaccharide and is a dominant component of dietary fiber. Bacteria in the distal human gastrointestinal tract produce xylanase enzymes to initiate the degradation of this complex heteropolymer. These xylanases typically derive from glycoside hydrolase (GH) families 10 and 11; however, analysis of the genome sequence of the xylan-degrading human gut bacterium Bacteroides intestinalis DSM 17393 revealed the presence of two putative GH8 xylanases. In the current study, we demonstrate that the two genes encode enzymes that differ in activity. The xyn8A gene encodes an endoxylanase (Xyn8A), and rex8A encodes a reducing-end xylose-releasing exo-oligoxylanase (Rex8A). Xyn8A hydrolyzed both xylopentaose (X5) and xylohexaose (X6) to a mixture of xylobiose (X2) and xylotriose (X3), while Rex8A hydrolyzed X3 through X6 to a mixture of xylose (X1) and X2. Moreover, rex8A is located downstream of a GH3 gene (xyl3A) that was demonstrated to exhibit β-xylosidase activity and would be able to further hydrolyze X2 to X1. Mutational analyses of putative active site residues of both Xyn8A and Rex8A confirm their importance in catalysis by these enzymes. Recent genome sequences of gut bacteria reveal an increase in GH8 Rex enzymes, especially among the Bacteroidetes, indicating that these genes contribute to xylan utilization in the human gut.
CitationTwo New Xylanases with Different Substrate Specificities from the Human Gut Bacterium Bacteroides intestinalis DSM 17393 2014, 80 (7):2084 Applied and Environmental Microbiology
PublisherAmerican Society for Microbiology
PubMed Central IDPMC3993143
- The Glycoside Hydrolase Family 8 Reducing-End Xylose-Releasing Exo-oligoxylanase Rex8A from Paenibacillus barcinonensis BP-23 Is Active on Branched Xylooligosaccharides.
- Authors: Valenzuela SV, Lopez S, Biely P, Sanz-Aparicio J, Pastor FI
- Issue date: 2016 Sep 1
- A novel reducing-end xylose-releasing exo-oligoxylanase (PphRex8A) from Paenibacillus physcomitrellae XB.
- Authors: Wang L, Zhang XJ, Li YH
- Issue date: 2022 Oct
- Structural analysis of the reducing-end xylose-releasing exo-oligoxylanase Rex8A from Paenibacillus barcinonensis BP-23 deciphers its molecular specificity.
- Authors: Jiménez-Ortega E, Valenzuela S, Ramírez-Escudero M, Pastor FJ, Sanz-Aparicio J
- Issue date: 2020 Dec
- The effect of an oligosaccharide reducing-end xylanase, BhRex8A, on the synergistic degradation of xylan backbones by an optimised xylanolytic enzyme cocktail.
- Authors: Malgas S, Pletschke BI
- Issue date: 2019 Mar
- Xylan utilization in human gut commensal bacteria is orchestrated by unique modular organization of polysaccharide-degrading enzymes.
- Authors: Zhang M, Chekan JR, Dodd D, Hong PY, Radlinski L, Revindran V, Nair SK, Mackie RI, Cann I
- Issue date: 2014 Sep 2