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Difference between revisions of "Glycoside Hydrolase Family 63"
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Genes for the GH63 enzymes have also been found in archaea and bacteria, but archaea and bacteria have been reported not to produce eukaryotic ''N''-linked oligosacharides, and the principal substrates of archaeal and bacterial GH63 enzymes are still unclear. A bacterial GH63 enzyme, ''Escherichia coli'' YgjK, showed the highest activity for the α-1,3-glucosidic linkage of nigerose (Glc-α-1,3-Glc) among commercially available sugars <cite>Kurataka2008</cite>. | Genes for the GH63 enzymes have also been found in archaea and bacteria, but archaea and bacteria have been reported not to produce eukaryotic ''N''-linked oligosacharides, and the principal substrates of archaeal and bacterial GH63 enzymes are still unclear. A bacterial GH63 enzyme, ''Escherichia coli'' YgjK, showed the highest activity for the α-1,3-glucosidic linkage of nigerose (Glc-α-1,3-Glc) among commercially available sugars <cite>Kurataka2008</cite>. | ||
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== Kinetics and Mechanism == | == Kinetics and Mechanism == | ||
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== Catalytic Residues == | == Catalytic Residues == | ||
The catalytic residues were inferred by comparing the (α/α)<sub>6</sub> barrel domain of the GH63 enzyme, ''E. coli'' YgjK, with those of GH15 and GH37 enzymes. The catalytic [[general acid]] is predicted as an aspartate residue (Asp501 in ''E. coli'' YgjK), and the [[general base]] is considered as a glutamate residue (Glu727 in ''E. coli'' YgjK) <cite>Kurataka2008</cite>. | The catalytic residues were inferred by comparing the (α/α)<sub>6</sub> barrel domain of the GH63 enzyme, ''E. coli'' YgjK, with those of GH15 and GH37 enzymes. The catalytic [[general acid]] is predicted as an aspartate residue (Asp501 in ''E. coli'' YgjK), and the [[general base]] is considered as a glutamate residue (Glu727 in ''E. coli'' YgjK) <cite>Kurataka2008</cite>. | ||
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== Three-dimensional structures == | == Three-dimensional structures == | ||
| − | + | The crystal structures of two bacterial GH63 proteins, ''E. coli'' YgjK <cite>Kurataka2008</cite> and ''Thermus thermophilus'' uncharacterised protein TTHA0978 ([{{PDBlink}}2z07 PDB 2z07]), have been reported. The catalytic domain consists of (α/α)<sub>6</sub> barrel fold. | |
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== Family Firsts == | == Family Firsts == | ||
Revision as of 23:31, 20 April 2011
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: ^^^Takashi Tonozuka^^^
- Responsible Curator: ^^^Takashi Tonozuka^^^
| Glycoside Hydrolase Family GH63 | |
| Clan | GH-G |
| Mechanism | inverting |
| Active site residues | Inferred |
| CAZy DB link | |
| https://www.cazy.org/GH63.html | |
Substrate specificities
Glycoside hydrolases of this family are exo-acting inverting enzymes. The most commonly characterized activity of the eukaryotic enzymes is processing α-glucosidase I (EC 3.2.1.106), which specifically hydrolyzes the terminal α-1,2-glucosidic linkage in the N-linked oligosaccharide precursor, Glc3Man9GlcNAc2. The enzymatic properties of Cwh41p, a processing α-glucosidase I from Saccharomyces cerevisiae, have been most intensively studied.
Genes for the GH63 enzymes have also been found in archaea and bacteria, but archaea and bacteria have been reported not to produce eukaryotic N-linked oligosacharides, and the principal substrates of archaeal and bacterial GH63 enzymes are still unclear. A bacterial GH63 enzyme, Escherichia coli YgjK, showed the highest activity for the α-1,3-glucosidic linkage of nigerose (Glc-α-1,3-Glc) among commercially available sugars [1].
Kinetics and Mechanism
Family GH63 enzymes are inverting enzymes, as first shown by NMR on a processing α-glucosidase I from S. cerevisiae [2].
Catalytic Residues
The catalytic residues were inferred by comparing the (α/α)6 barrel domain of the GH63 enzyme, E. coli YgjK, with those of GH15 and GH37 enzymes. The catalytic general acid is predicted as an aspartate residue (Asp501 in E. coli YgjK), and the general base is considered as a glutamate residue (Glu727 in E. coli YgjK) [1].
Three-dimensional structures
The crystal structures of two bacterial GH63 proteins, E. coli YgjK [1] and Thermus thermophilus uncharacterised protein TTHA0978 (PDB 2z07), have been reported. The catalytic domain consists of (α/α)6 barrel fold.
Family Firsts
- First stereochemistry determination
- Cwh41p, a processing α-glucosidase I from Saccharomyces cerevisiae [2].
- First catalytic nucleophile identification
- Cite some reference here, with a short (1-2 sentence) explanation [1].
- First general acid/base residue identification
- Cite some reference here, with a short (1-2 sentence) explanation [1].
- First 3-D structure
- Cite some reference here, with a short (1-2 sentence) explanation [1].
References
- Kurakata Y, Uechi A, Yoshida H, Kamitori S, Sakano Y, Nishikawa A, and Tonozuka T. (2008). Structural insights into the substrate specificity and function of Escherichia coli K12 YgjK, a glucosidase belonging to the glycoside hydrolase family 63. J Mol Biol. 2008;381(1):116-28. DOI:10.1016/j.jmb.2008.05.061 |
- Palcic MM, Scaman CH, Otter A, Szpacenko A, Romaniouk A, Li YX, and Vijay IK. (1999). Processing alpha-glucosidase I is an inverting glycosidase. Glycoconj J. 1999;16(7):351-5. DOI:10.1023/a:1007096011392 |