Glycoside Hydrolase Family 187

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Glycoside Hydrolase Family GH187
Clan	not known
Mechanism	not known
Active site residues	not known
CAZy DB link
https://www.cazy.org/GH187.html

Substrate specificities

Members of glycoside hydrolase family 187 have been shown to exhibit α-1,3-L-fucanase activity. The first member of this family, Fun187A from a marine bacterium Wenyingzhuangia aestuarii OF219, specifically hydrolyzes the α-1,3-L-fucoside bonds between non-sulfated and 2-O-sulfated fucose residuess in the sulfated fucan oligosaccharide α-L-Fucp(2,4OSO₃^-)-1→3-α-L-Fucp-1→3-α-L-Fucp(2OSO₃^-)-1→3-α-L-Fucp(2OSO₃^-) in an endo-acting manner [1]. Meanwhile, one homologue of Fun187A displays activities toward sulfated fucans from Holothuria tubulosa and Isostichopus badionotus, namely WP_159020740.1 [1].

Figure 1. The phylogenetic tree of GH187 homologues. Sequences confirmed to exhibit α-1,3-L-fucanase activity were highlighted in red triangles.

Kinetics and Mechanism

The catalytic mechanism of GH187 has not been identified. As mentioned in the report, Fun187A showed no transglycosylating activity in the tested acceptor substrates, such as D-glucose, D-galactose, D-mannose, D-fructose, L-fucose, D-glucosamine, N-acetyl-D-glucosamine, glycerin, and methanol [1].

Catalytic Residues

No catalytic residues have been identified in this glycoside hydrolase family at present.

Three-dimensional structures

No three-dimensional structure has been solved in this glycoside hydrolase family at present.

Family Firsts

First stereochemistry determination: Not yet identified.
First catalytic nucleophile identification: Not yet identified.
First general acid/base residue identification: Not yet identified.
First 3-D structure: Not yet identified.

References

Shen J, Zheng L, Zhang Y, Chen G, Mei X, Chang Y, and Xue C. (2024). Discovery of a catalytic domain defines a new glycoside hydrolase family containing endo-1,3-fucanase. Carbohydr Polym. 2024;323:121442. DOI:10.1016/j.carbpol.2023.121442 | PubMed ID:37940306 [Shen2024]