Glycoside Hydrolase Family 82

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• Authors: ^^^Gurvan Michel^^^ and ^^^Mirjam Czjzek^^^
• Responsible Curator: ^^^Mirjam Czjzek^^^

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Glycoside Hydrolase Family GH82
Clan	none
Mechanism	inverting
Active site residues	not known
CAZy DB link
http://www.cazy.org/fam/GH82.html

Substrate specificities

The two known members of glycoside hydrolase family 82 enzymes cleave the β-1,4 galactosidic bond of the marine algal polysaccharide iota-carrageenan [1] yielding products of the neocarrabiose series.

Kinetics and Mechanism

Family 82 enzymes are inverting enzymes, as first shown by NMR [1] on the iota-carrageenase from Alteromonas fortis.

Catalytic Residues

From structural analysis predicted to be two out of the three candidate amino acids Glu245, Asp247 or Glu310 in the A. fortis iota-carrageenase [2].

Three-dimensional structures

To date, a crystal structure has only been determined for the iota-carrageenase from A. fortis [2]. The crystal structure of a product complex has shed light on the existance of domain movement of domain A that is closed around the oligo-carrageenan in the complexed form and open in the uncomplexed enzyme [3].

Family Firsts

First sequence identification and family creation

iota-carrageenase sequences have been first reported for enzymes from A. fortis and Z. galactanivorans [1].

First sterochemistry determination

GH82 enzymes are inverting as shown by NMR [1].

First general acid residue identification

not determined yet.

First general base residue identification

not determined yet.

First 3-D structure

iota-carrageenase from A. fortis [2]. The structure belongs to the β-helix fold (PDB 1h80 and PDB 1ktw).

References

1. Barbeyron T, Michel G, Potin P, Henrissat B, and Kloareg B. (2000). iota-Carrageenases constitute a novel family of glycoside hydrolases, unrelated to that of kappa-carrageenases. J Biol Chem. 2000;275(45):35499-505. DOI:10.1074/jbc.M003404200 |
2. Michel G, Chantalat L, Fanchon E, Henrissat B, Kloareg B, and Dideberg O. (2001). The iota-carrageenase of Alteromonas fortis. A beta-helix fold-containing enzyme for the degradation of a highly polyanionic polysaccharide. J Biol Chem. 2001;276(43):40202-9. DOI:10.1074/jbc.M100670200 |
3. Michel G, Helbert W, Kahn R, Dideberg O, and Kloareg B. (2003). The structural bases of the processive degradation of iota-carrageenan, a main cell wall polysaccharide of red algae. J Mol Biol. 2003;334(3):421-33. DOI:10.1016/j.jmb.2003.09.056 |