33674431, Appl Environ Microbiol. 2021 Apr 27;87(10):e02690-20. doi: 10.1128/AEM.02690-20. Print 2021 Apr 27.

Characterization method

enzyme activity assay,high performance anion exchange chromatography,recombinant protein expression,NMR,gene deletion mutant and growth assay

Genomic accession number


Nucelotide position range







Bifidobacterium longum JCM 7052/216816

Degradation or Biosynthesis


Cluster number


Gene name

Gene position

Gene type

Found by CGCFinder?

- 1 - 1014 (-) TF: DBD-Pfam|LacI,DBD-SUPERFAMILY|0036955 No
- 1353 - 2612 (+) STP: STP|SBP_bac_1 No
- 2791 - 3717 (+) TC: gnl|TC-DB|O51924|3.A.1.1.7 Yes
- 3719 - 4582 (+) TC: gnl|TC-DB|Q8NMV5|3.A.1.1.45 Yes
- 4613 - 6763 (+) CAZyme: GH36|GH36 Yes
- 7101 - 10388 (+) CAZyme: GH39 Yes
- 10611 - 11900 (+) CDS No




33674431, Appl Environ Microbiol. 2021 Apr 27;87(10):e02690-20. doi: 10.1128/AEM.02690-20. Print 2021 Apr 27.


Novel 3-O-alpha-d-Galactosyl-alpha-l-Arabinofuranosidase for the Assimilation of Gum Arabic Arabinogalactan Protein in Bifidobacterium longum subsp. longum.


Sasaki Y, Horigome A, Odamaki T, Xiao JZ, Ishiwata A, Ito Y, Kitahara K, Fujita K


Gum arabic arabinogalactan (AG) protein (AGP) is a unique dietary fiber that is degraded and assimilated by only specific strains of Bifidobacterium longum subsp. longum Here, we identified a novel 3-O-alpha-d-galactosyl-alpha-l-arabinofuranosidase (GAfase) from B. longum JCM7052 and classified it into glycoside hydrolase family 39 (GH39). GAfase released alpha-d-Galp-(1-->3)-l-Ara and beta-l-Arap-(1-->3)-l-Ara from gum arabic AGP and beta-l-Arap-(1-->3)-l-Ara from larch AGP, and the alpha-d-Galp-(1-->3)-l-Ara release activity was found to be 594-fold higher than that of beta-l-Arap-(1-->3)-l-Ara. The GAfase gene was part of a gene cluster that included genes encoding a GH36 alpha-galactosidase candidate and ABC transporters for the assimilation of the released alpha-d-Galp-(1-->3)-l-Ara in B. longum Notably, when alpha-d-Galp-(1-->3)-l-Ara was removed from gum arabic AGP, it was assimilated by both B. longum JCM7052 and the nonassimilative B. longum JCM1217, suggesting that the removal of alpha-d-Galp-(1-->3)-l-Ara from gum arabic AGP by GAfase permitted the cooperative action with type II AG degradative enzymes in B. longum The present study provides new insight into the mechanism of gum arabic AGP degradation in B. longumIMPORTANCE Bifidobacteria harbor numerous carbohydrate-active enzymes that degrade several dietary fibers in the gastrointestinal tract. B. longum JCM7052 is known to exhibit the ability to assimilate gum arabic AGP, but the key enzyme involved in the degradation of gum arabic AGP remains unidentified. Here, we cloned and characterized a GH39 3-O-alpha-d-galactosyl-alpha-l-arabinofuranosidase (GAfase) from B. longum JCM7052. The enzyme was responsible for the release of alpha-d-Galp-(1-->3)-l-Ara and beta-l-Arap-(1-->3)-l-Ara from gum arabic AGP. The presence of a gene cluster including the GAfase gene is specifically observed in gum arabic AGP assimilative strains. However, GAfase carrier strains may affect GAfase noncarrier strains that express other type II AG degradative enzymes. These findings provide insights into the bifidogenic effect of gum arabic AGP.