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Difference between revisions of "Polysaccharide Lyase Family 4"
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== Substrate specificities == | == Substrate specificities == | ||
| − | The main activity assigned to characterized enzymes in PL4 is degradation of the plant cell wall component rhamnogalacturonan I, a component of pectin hairy regions. Rhamnogalacturonan I is a heteropolymer built up by the disaccharide unit [α-L-Rha-(1,4)-α-D-GalUA-(1,2)], with often extensive branching (arabinans, galactans and arabinogalactans)at the O2 and O3 of the galacturonic acid units. The best characterized enzymes in the family cleave the α-1,4-glycosidic bonds between L-rhamnose and D-galacturonic acids. | + | The main activity assigned to characterized enzymes in PL4 is degradation of the plant cell wall component rhamnogalacturonan I, a component of pectin hairy regions. Rhamnogalacturonan I is a heteropolymer built up by the disaccharide unit [α-L-Rha-(1,4)-α-D-GalUA-(1,2)], with often extensive branching (arabinans, galactans and arabinogalactans)at the O2 and O3 of the galacturonic acid units. The best characterized enzymes in the family, exemplified by the ''Aspergillus aculeatus'' Rhamnogalacturonan Lyase (AaRGL4)cleave the α-1,4-glycosidic bonds between L-rhamnose and D-galacturonic acids. Biochemical studies by Mutter et al. show that the minimum substrate requirement is a deacetylated dodecamer, with preferential cleavage four residues from the reducing end Rha, but the structural studies (see below) have demonstrated that smaller ligands can be bound. |
In the meantime, please see these references for an essential introduction to the CAZy classification system: <cite>DaviesSinnott2008 Cantarel2009</cite>. | In the meantime, please see these references for an essential introduction to the CAZy classification system: <cite>DaviesSinnott2008 Cantarel2009</cite>. | ||
Revision as of 00:02, 4 September 2014
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: Leila Lo Leggio and Sine Larsen
- Responsible Curator: ^^^Leila LoLeggio^^^
| Polysaccharide Lyase Family PL4 | |
| Mechanism | β-elimination |
| Charge neutraliser | none |
| Active site residues | known |
| CAZy DB link | |
| https://www.cazy.org/PL4.html | |
Substrate specificities
The main activity assigned to characterized enzymes in PL4 is degradation of the plant cell wall component rhamnogalacturonan I, a component of pectin hairy regions. Rhamnogalacturonan I is a heteropolymer built up by the disaccharide unit [α-L-Rha-(1,4)-α-D-GalUA-(1,2)], with often extensive branching (arabinans, galactans and arabinogalactans)at the O2 and O3 of the galacturonic acid units. The best characterized enzymes in the family, exemplified by the Aspergillus aculeatus Rhamnogalacturonan Lyase (AaRGL4)cleave the α-1,4-glycosidic bonds between L-rhamnose and D-galacturonic acids. Biochemical studies by Mutter et al. show that the minimum substrate requirement is a deacetylated dodecamer, with preferential cleavage four residues from the reducing end Rha, but the structural studies (see below) have demonstrated that smaller ligands can be bound.
In the meantime, please see these references for an essential introduction to the CAZy classification system: [1, 2].
Kinetics and Mechanism
Content is to be added here.
Catalytic Residues
Content is to be added here.
Three-dimensional structures
Content is to be added here.
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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Davies, G.J. and Sinnott, M.L. (2008) Sorting the diverse: the sequence-based classifications of carbohydrate-active enzymes. Biochem. J. (BJ Classic Paper, online only). DOI: 10.1042/BJ20080382
- Cantarel BL, Coutinho PM, Rancurel C, Bernard T, Lombard V, and Henrissat B. (2009). The Carbohydrate-Active EnZymes database (CAZy): an expert resource for Glycogenomics. Nucleic Acids Res. 2009;37(Database issue):D233-8. DOI:10.1093/nar/gkn663 |