title: GH115 α-glucuronidase and GH11 xylanase from Paenibacillus sp. JDR-2: potential roles in processing glucuronoxylans.
abstract: Paenibacillus sp. JDR-2 (Pjdr2) has been studied as a model for development of bacterial biocatalysts for efficient processing of xylans, methylglucuronoxylan, and methylglucuronoarabinoxylan, the predominant hemicellulosic polysaccharides found in dicots and monocots, respectively. Pjdr2 produces a cell-associated GH10 endoxylanase (Xyn10A1) that catalyzes depolymerization of xylans to xylobiose, xylotriose, and methylglucuronoxylotriose with methylglucuronate-linked α-1,2 to the nonreducing terminal xylose. A GH10/GH67 xylan utilization regulon includes genes encoding an extracellular cell-associated Xyn10A1endoxylanase and an intracellular GH67 α-glucuronidase active on methylglucuronoxylotriose generated by Xyn10A1but without activity on methylglucuronoxylotetraose generated by a GH11 endoxylanase. The sequenced genome of Pjdr2 contains three paralogous genes potentially encoding GH115 α-glucuronidases found in certain bacteria and fungi. One of these, Pjdr2_5977, shows enhanced expression during growth on xylans along with Pjdr2_4664 encoding a GH11 endoxylanase. Here, we show that Pjdr2_5977 encodes a GH115 α-glucuronidase, Agu115A, with maximal activity on the aldouronate methylglucuronoxylotetraose selectively generated by a GH11 endoxylanase Xyn11 encoded by Pjdr2_4664. Growth of Pjdr2 on this methylglucuronoxylotetraose supports a process for Xyn11-mediated extracellular depolymerization of methylglucuronoxylan and Agu115A-mediated intracellular deglycosylation as an alternative to the GH10/GH67 system previously defined in this bacterium. A recombinantly expressed enzyme encoded by the Pjdr2 agu115A gene catalyzes removal of 4-O-methylglucuronate residues α-1,2 linked to internal xylose residues in oligoxylosides generated by GH11 and GH30 xylanases and releases methylglucuronate from polymeric methylglucuronoxylan. The GH115 α-glucuronidase from Pjdr2 extends the discovery of this activity to members of the phylum Firmicutes and contributes to a novel system for bioprocessing hemicelluloses.
authors.affiliation: Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA.|Xycrobe Therapeutics Inc., 3210 Merryfield Row, San Diego,, CA, 92121,, USA.
authors.forename: Mun Su
authors.initials: MS
authors.lastname: Rhee
authors.affiliation: Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA.|Department of Chemistry, Vanderbilt University, Nashville, TN, 37235,, USA.
authors.forename: Neha
authors.initials: N
authors.lastname: Sawhney
authors.affiliation: Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA.
authors.forename: Young Sik
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA.|Department of Materials Science and Engineering, Massachusetts Institute of Technology, 6-113, Cambridge, MA, 02139,, USA.
authors.forename: Hyun Jee
authors.initials: HJ
authors.lastname: Rhee
authors.affiliation: Department of Chemistry, Physics and Geology, Winthrop University, Rock Hill, SC, 29733, USA.
authors.forename: Jason C
authors.initials: JC
authors.lastname: Hurlbert
authors.affiliation: Forest Products Laboratory, United States Forest Service, The United States Department of Agriculture, Madison, Madison,, WI, 53726, USA.
authors.forename: Franz J
authors.initials: FJ
authors.lastname: St John
authors.affiliation: Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA.
authors.forename: Guang
authors.initials: G
authors.lastname: Nong
authors.affiliation: Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Rice
authors.affiliation: Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA. jpreston@ufl.edu.
authors.forename: James F
authors.identifier: http://orcid.org/0000-0002-3094-3312
authors.initials: JF
authors.lastname: Preston
mesh_terms: D043364:Endo-1,4-beta Xylanases / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000378:metabolism*; D056507:Paenibacillus / Q000201:enzymology* / Q000378:metabolism*; D014990:Xylans / Q000378:metabolism*
chemical_list: D014990:Xylans; C038910:glucuronoxylan; D006026:Glycoside Hydrolases; C096734:alpha-glucuronidase; D043364:Endo-1,4-beta Xylanases
keywords: Biofuels and chemicals; GH11 endoxylanase; GH115 α-glucuronidase; Paenibacillus sp. JDR-2; Xylans