Glycoside Hydrolase Family 172

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• Author: Toma Kashima
• Responsible Curator: Shinya Fushinobu

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Glycoside Hydrolase Family GH172
Clan	None
Mechanism	retaining
Active site residues	known
CAZy DB link
https://www.cazy.org/GH172.html

Substrate specificities

Glycoside hydrolase family 172 (GH172) includes α-D-arabinofuranosidases and α-D-fructofuranosidases. This family was established following the discovery of αFFase1 from Bifidobacterium dentium by Kashima et al. in 2021 [1]. αFFase1 hydrolyzes the alkylated glycosides Me-α-D-Araf and Me-α-D-Fruf. In nature, it catalyzes the dehydrating condensation reaction of inulobiose (β-D-Fruf-(2→1)-α-D-Fruf) to difructose dianhydride I (DFA I, α-D-Fruf-1,2′:2,1′-β-D-Fruf). The dehydrating condensation reaction reaches equilibrium when the ratio of DFA and inulobiose is 9:1. αFFase1 is less specific for D-Fru at the non-reducing end and is able to catalyze the dehydrating condensation of β-D-Frup-(2→1)-α-D-Fruf to diheterolevulosan II (DHL II, α-D-Frup-1,2′:2,1′-β-D-Fruf). Physiologically, it is believed that after degradation of DFA I to inulobiose, inulobiose is degraded to D-Fru by Glycoside Hydrolase Family 32 β-D-fructofuranosidase, and then the produced monosaccharides are metabolized by the microorganism. DFA I is an oligosaccharide found in caramel, and since the degradation system of DFA I by bifidobacteria has been clarified, DFA I has attracted a certain attention in the food industry.

Also, some GH172 enzymes which physiologically functions as α-D-arabinofuranosidase, was reported in 2023 by Al-Jourani et al. (DgGH172a, DgGH172b, DgGH172c [2]) and Shimokawa et al. (ExoMA1 [3]). In particular, ExoMA1 was compared in detail with αFFase1, and it was found that its α-D-fructofuranosidase activity is extremely weak. These enzymes are believed to be involved in the degradation system of d-arabinan in the cell walls of Mycobacteria and other acid-fast bacteria, and are expected to be applied to the development of therapeutic, preventive, and diagnostic agents for infectious diseases. Authors may get an idea of what to put in each field from Curator Approved Glycoside Hydrolase Families. (TIP: Right click with your mouse and open this link in a new browser window...)

In the meantime, please see these references for an essential introduction to the CAZy classification system: [4, 5].

Kinetics and Mechanism

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Catalytic Residues

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Three-dimensional structures

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Family Firsts

First stereochemistry determination

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First catalytic nucleophile identification

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First general acid/base residue identification

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First 3-D structure

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References

1. Kashima T, Okumura K, Ishiwata A, Kaieda M, Terada T, Arakawa T, Yamada C, Shimizu K, Tanaka K, Kitaoka M, Ito Y, Fujita K, and Fushinobu S. (2021). Identification of difructose dianhydride I synthase/hydrolase from an oral bacterium establishes a novel glycoside hydrolase family. J Biol Chem. 2021;297(5):101324. DOI:10.1016/j.jbc.2021.101324 |
2. Al-Jourani O, Benedict ST, Ross J, Layton AJ, van der Peet P, Marando VM, Bailey NP, Heunis T, Manion J, Mensitieri F, Franklin A, Abellon-Ruiz J, Oram SL, Parsons L, Cartmell A, Wright GSA, Baslé A, Trost M, Henrissat B, Munoz-Munoz J, Hirt RP, Kiessling LL, Lovering AL, Williams SJ, Lowe EC, and Moynihan PJ. (2023). Identification of D-arabinan-degrading enzymes in mycobacteria. Nat Commun. 2023;14(1):2233. DOI:10.1038/s41467-023-37839-5 |

3. Shimokawa, M., Ishiwata, A., Kashima, T. et al. (2023) Identification and characterization of endo-α-, exo-α-, and exo-β-D-arabinofuranosidases degrading lipoarabinomannan and arabinogalactan of mycobacteria. Nature Communications 14, 5803. [1]

4. Davies, G.J. and Sinnott, M.L. (2008) Sorting the diverse: the sequence-based classifications of carbohydrate-active enzymes. The Biochemist, vol. 30, no. 4., pp. 26-32. Download PDF version.

5. Cantarel BL, Coutinho PM, Rancurel C, Bernard T, Lombard V, and Henrissat B. (2009). The Carbohydrate-Active EnZymes database (CAZy): an expert resource for Glycogenomics. Nucleic Acids Res. 2009;37(Database issue):D233-8. DOI:10.1093/nar/gkn663 |