Glycoside Hydrolase Family 192

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• Author: Masahiro Nakajima
• Responsible Curator: Masahiro Nakajima

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Glycoside Hydrolase Family GH192
Clan	GH-S
Mechanism	inverting
Active site residues	not known
CAZy DB link
https://www.cazy.org/GH192.html

Substrate specificities

PgSGL1(H744_1c0224, KEGG) and PgSGL2(H744_2c1936, KEGG) from Photobacterium gaetbulicola and EeSGL1(A0A081KBI6, Uniprot) from Endozoicomonas elysicola are characterized. The three enzymes are specific to β-1,2-glucan among polysaccharides. They hydrolyze β-1,2-glucan endolytically to produce β-1,2-glucooligosaccharides [1].

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...)

Kinetics and Mechanism

PgSGL1 follows anomer-inverting mechanism, which is determined by measuring change of optical rotation during hydrolysis of β-1,2-glucan [1].

Catalytic Residues

Catalytic residues are not determined. However, the general acid is considered as E221 (EeSGL1) as this residue is well superimposed with the general acid (E262) in GH162 β-1,2-glucanase from Talaromyces funiculosus [2].

Three-dimensional structures

A ligand-free structure of EeSGL1 is solved in 2025 [1].

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. Nakajima M, Tanaka N, Motouchi S, Kobayashi K, Shimizu H, Abe K, Hosoyamada N, Abara N, Morimoto N, Hiramoto N, Nakata R, Takashima A, Hosoki M, Suzuki S, Shikano K, Fujimaru T, Imagawa S, Kawadai Y, Wang Z, Kitano Y, Nihira T, Nakai H, and Taguchi H. (2025). New glycoside hydrolase families of β-1,2-glucanases. Protein Sci. 2025;34(6):e70147. DOI:10.1002/pro.70147 |
2. Tanaka N, Nakajima M, Narukawa-Nara M, Matsunaga H, Kamisuki S, Aramasa H, Takahashi Y, Sugimoto N, Abe K, Terada T, Miyanaga A, Yamashita T, Sugawara F, Kamakura T, Komba S, Nakai H, and Taguchi H. (2019). Identification, characterization, and structural analyses of a fungal endo-β-1,2-glucanase reveal a new glycoside hydrolase family. J Biol Chem. 2019;294(19):7942-7965. DOI:10.1074/jbc.RA118.007087 |