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Difference between revisions of "Glycoside Hydrolase Family 136"
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The X-ray crystal structure of the catalytic domain, LnbXc(31-625) revealed a right-handed β helix fold. | The X-ray crystal structure of the catalytic domain, LnbXc(31-625) revealed a right-handed β helix fold. | ||
Three forms, ligand free (2.36 Å resolution), LNB complex (1.82 Å), and GNB complex (2.70 Å) were determined. | Three forms, ligand free (2.36 Å resolution), LNB complex (1.82 Å), and GNB complex (2.70 Å) were determined. | ||
| − | [[file:LnbXc.png|200px|right]] | + | [[file:LnbXc.png|200px|right|'''Figure 1: '''Overall structure of LnbXc with LNB (cyan) and two Ca2+ ions (orange).]] |
== Family Firsts == | == Family Firsts == | ||
Revision as of 23:45, 12 August 2020
This page is currently under construction. This means that the Responsible Curator has deemed that the page's content is not quite up to CAZypedia's standards for full public consumption. All information should be considered to be under revision and may be subject to major changes.
- Author: ^^^Chihaya Yamada^^^
- Responsible Curator: ^^^Shinya Fushinobu^^^
| Glycoside Hydrolase Family GH136 | |
| Clan | GH-N |
| Mechanism | retaining |
| Active site residues | known |
| CAZy DB link | |
| https://www.cazy.org/GH136.html | |
Substrate specificities
This family of glycoside hydrolases contains lacto-N-biosidase, as demonstrated for LnbX from Bifidobacterium longum JCM 1217 [1]. LnbX liberates Galβ1-3GlcNAc(lacto-N-biose I, LNB) and lactose from lacto-N-tetraose, the main component of human milk oligosaccharides. It hydrolyzed the linkage GlcNAcβ1-3Gal in lacto-N-hexaose, lacto-N-fucopentaose I, and sialyllacto-N-tetraose a of human milk oligosaccharides as substrate of LnbX in the GH136. In addition, LnbX liberates Galβ1-3GalNAc (GNB) from the sugar chains of globo- and ganglio-series glycosphingolipids [2].
GH136 lacto-N-biosidase required neighboring chaperon gene for folding. Rarely, chaperone-like gene fused to lacto-N-biosidase gene in case of ErGH136I and ErGH136IIfrom Eubacterium ramulus [3].
Kinetics and Mechanism
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Catalytic Residues
The nucleophile is Asp418. The catalytic acid/base is Asp411 via water molecule.
Three-dimensional structures
The X-ray crystal structure of the catalytic domain, LnbXc(31-625) revealed a right-handed β helix fold. Three forms, ligand free (2.36 Å resolution), LNB complex (1.82 Å), and GNB complex (2.70 Å) were determined.
Family Firsts
- First stereochemistry determination
- Content is to be added here.
- First catalytic nucleophile identification
- Content is to be added here.
- First general acid/base residue identification
- Content is to be added here.
- First 3-D structure
- Content is to be added here.
References
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