title: The GH67 α-glucuronidase of Paenibacillus curdlanolyticus B-6 removes hexenuronic acid groups and facilitates biodegradation of the model xylooligosaccharide hexenuronosyl xylotriose.
abstract: 4-O-Methylglucuronic acid (MeGlcA) side groups attached to the xylan backbone through α-1,2 linkages are converted to hexenuronic acid (HexA) during alkaline pulping. α-Glucuronidase (EC 3.2.1.139) hydrolyzes 1,2-linked MeGlcA from xylooligosaccharides. To determine whether α-glucuronidase can also hydrolyze HexA-decorated xylooligosaccharides, a gene encoding α-glucuronidase (AguA) was cloned from Paenibacillus curdlanolyticus B-6. The purified protein degraded hexenuronosyl xylotriose (ΔX3), a model substrate prepared from kraft pulp. AguA released xylotriose and HexA from ΔX3, but the Vmax and kcat values for ΔX3 were lower than those for MeGlcA, indicating that HexA side groups may affect the hydrolytic activity. To explore the potential for biological bleaching, ΔX3 degradation was performed using intracellular extract from P. curdlanolyticus B-6. The intracellular extract, with synergistic α-glucuronidase and β-xylosidase activities, degraded ΔX3 to xylose and HexA. These results indicate that α-glucuronidase can be used to remove HexA from ΔX3 derived from pulp, reducing the need for chemical treatments in the pulping process.
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
authors.forename: Krisna
authors.initials: K
authors.lastname: Septiningrum
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohi
authors.affiliation: Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkuntien, Bangkok 10150, Thailand.
authors.forename: Rattiya
authors.initials: R
authors.lastname: Waeonukul
authors.affiliation: Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkuntien, Bangkok 10150, Thailand.
authors.forename: Patthra
authors.initials: P
authors.lastname: Pason
authors.affiliation: Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkuntien, Bangkok 10150, Thailand.
authors.forename: Chakrit
authors.initials: C
authors.lastname: Tachaapaikoon
authors.affiliation: School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkuntien, Bangkok 10150, Thailand.
authors.forename: Khanok
authors.initials: K
authors.lastname: Ratanakhanokchai
authors.affiliation: Department of Chemical Technology, Faculty of Science and Technology, Suan Dusit Rajabhat University, 295 Rajasrima Road, Dusit, Bangkok 10300, Thailand.
authors.forename: Junjarus
authors.initials: J
authors.lastname: Sermsathanaswadi
authors.affiliation: Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
authors.forename: Lan
authors.initials: L
authors.lastname: Deng
authors.affiliation: Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
authors.forename: Panida
authors.initials: P
authors.lastname: Prawitwong
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan. Electronic address: akosugi@affrc.go.jp.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kosugi
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002240:Carbohydrate Sequence; D005798:Genes, Bacterial; D005965:Glucuronates / Q000737:chemistry / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000235:genetics / Q000378:metabolism*; D006603:Hexuronic Acids / Q000737:chemistry / Q000378:metabolism; D006868:Hydrolysis; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D056507:Paenibacillus / Q000201:enzymology* / Q000235:genetics; D013379:Substrate Specificity; D014312:Trisaccharides / Q000737:chemistry / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D005965:Glucuronates; D006603:Hexuronic Acids; D009844:Oligosaccharides; D014312:Trisaccharides; C095263:hexenuronic acid; C570991:xylooligosaccharide; C515044:xylotriose; D006026:Glycoside Hydrolases; C096734:alpha-glucuronidase
keywords: GH67; Hexenuronic acid; Hexenuronosyl xylotriose; Paenibacillus curdlanolyticus; α-Glucuronidase