PUL ID

PUL0289

PubMed

29588659, Biotechnol Biofuels. 2018 Mar 22;11:74. doi: 10.1186/s13068-018-1074-3. eCollection 2018.

Characterization method

enzyme activity assay

Genomic accession number

CP000685.1

Nucelotide position range

4598617-4627427

Substrate

xylan

Loci

Fjoh_3871-Fjoh_3882

Species

Flavobacterium johnsoniae/986

Degradation or Biosynthesis

degradation

Cluster number

1

Gene name

Gene position

Gene type

Found by CGCFinder?

- 1 - 3009 (-) TC: gnl|TC-DB|Q45780|1.B.14.6.1 Yes
- 3561 - 7682 (-) TF: DBD-Pfam|HTH_AraC,DBD-Pfam|HTH_AraC,DBD-SUPERFAMILY|0036286,DBD-SUPERFAMILY|0035607 Yes
- 7777 - 9720 (-) CAZyme: GH97 Yes
- 9781 - 12375 (-) CAZyme: GH3 Yes
- 12418 - 13974 (-) CAZyme: CBM22|GH43_10|GH43 Yes
- 14007 - 16304 (-) CAZyme: GH146 Yes
- 16323 - 18848 (-) CAZyme: GH115 Yes
- 18871 - 20553 (-) CAZyme: CE0|CE6|CE1 Yes
- 20605 - 21849 (-) other Yes
- 21905 - 23620 (-) CAZyme: GH43_12 Yes
- 23766 - 25706 (-) other Yes
- 25719 - 28811 (-) TC: gnl|TC-DB|Q45780|1.B.14.6.1 Yes

PUL ID

PUL0289

PubMed

29588659, Biotechnol Biofuels. 2018 Mar 22;11:74. doi: 10.1186/s13068-018-1074-3. eCollection 2018.

Title

A novel acetyl xylan esterase enabling complete deacetylation of substituted xylans.

Author

Razeq FM, Jurak E, Stogios PJ, Yan R, Tenkanen M, Kabel MA, Wang W, Master ER

Abstract

Background: Acetylated 4-O-(methyl)glucuronoxylan (GX) is the main hemicellulose in deciduous hardwood, and comprises a beta-(1-->4)-linked xylopyranosyl (Xylp) backbone substituted by both acetyl groups and alpha-(1-->2)-linked 4-O-methylglucopyranosyluronic acid (MeGlcpA). Whereas enzymes that target singly acetylated Xylp or doubly 2,3-O-acetyl-Xylp have been well characterized, those targeting (2-O-MeGlcpA)3-O-acetyl-Xylp structures in glucuronoxylan have remained elusive. Results: An unclassified carbohydrate esterase (FjoAcXE) was identified as a protein of unknown function from a polysaccharide utilization locus (PUL) otherwise comprising carbohydrate-active enzyme families known to target xylan. FjoAcXE was shown to efficiently release acetyl groups from internal (2-O-MeGlcpA)3-O-acetyl-Xylp structures, an activity that has been sought after but lacking in known carbohydrate esterases. FjoAcXE action boosted the activity of alpha-glucuronidases from families GH67 and GH115 by five and nine times, respectively. Moreover, FjoAcXE activity was not only restricted to GX, but also deacetylated (3-O-Araf)2-O-acetyl-Xylp of feruloylated xylooligomers, confirming the broad substrate range of this new carbohydrate esterase. Conclusion: This study reports the discovery and characterization of the novel carbohydrate esterase, FjoAcXE. In addition to cleaving singly acetylated Xylp, and doubly 2,3-O-acetyl-Xylp, FjoAcXE efficiently cleaves internal 3-O-acetyl-Xylp linkages in (2-O-MeGlcpA)3-O-acetyl-Xylp residues along with densely substituted and branched xylooligomers; activities that until now were missing from the arsenal of enzymes required for xylan conversion.