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Difference between revisions of "Polysaccharide Lyases"
Harry Brumer (talk | contribs) (Added some references.) |
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== Introduction == | == Introduction == | ||
| − | Polysaccharide lyases (PLs) cleave uronic acid-containing polysaccharides via a β-elimination mechanism to generate an unsaturated hexenuronic acid residue and a new reducing end at the point of cleavage <cite>Lombard2010 Garron2010</cite>. PLs have been grouped into families and subfamilies within the Carbohydrate-Active Enzyme (CAZy) framework and that the PLs included are restricted to those operating via ''syn''- and ''anti''-elimination mechanisms <cite>Lombard2010</cite>. In this way, they are distinct from carbon-oxygen lyases that modify polysaccharide composition. Broadly, the mechanism of PL action can be described as consisting of three events: (i) abstraction of the C-5 proton on the sugar ring of a uronic acid or ester by a charge stabilizing cation such as Ca<sup>2+</sup> or a basic amino acid side chain, (ii) stabilization of the resulting anion by charge delocalization onto the C-6 carbonyl group, and (iii) lytic cleavage of the O-4:C-4 bonding that is facilitated by proton donation from a catalytic acid <cite>Lombard2010</cite>. Please see the following reviews on PL classification, specificities, and structures <cite>Lombard2010 Garron2010</cite>. | + | Polysaccharide lyases (PLs) cleave uronic acid-containing polysaccharides via a β-elimination mechanism to generate an unsaturated hexenuronic acid residue and a new reducing end at the point of cleavage <cite>Lombard2010 Garron2010</cite>. PLs have been grouped into families and subfamilies within the Carbohydrate-Active Enzyme (CAZy) framework and that the PLs included are restricted to those operating via ''syn''- and ''anti''-elimination mechanisms <cite>Lombard2010</cite>. In this way, they are distinct from carbon-oxygen lyases that modify polysaccharide composition. Broadly, the mechanism of PL action can be described as consisting of three events: (i) abstraction of the C-5 proton on the sugar ring of a uronic acid or ester by a charge stabilizing cation such as Ca<sup>2+</sup> or a basic amino acid side chain, (ii) stabilization of the resulting anion by charge delocalization onto the C-6 carbonyl group, and (iii) lytic cleavage of the O-4:C-4 bonding that is facilitated by proton donation from a catalytic acid <cite>Lombard2010 YipWithers2006</cite>. Please see the following reviews on PL classification, specificities, mechanisms, and structures <cite>Lombard2010 Garron2010 Garron2014 YipWithers2006</cite>. |
== References == | == References == | ||
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#Lombard2010 pmid=20925655 | #Lombard2010 pmid=20925655 | ||
#Garron2010 pmid=20805221 | #Garron2010 pmid=20805221 | ||
| + | #Garron2014 pmid=25156747 | ||
| + | #YipWithers2006 pmid=16495121 | ||
</biblio> | </biblio> | ||
[[Category:Definitions and explanations]] | [[Category:Definitions and explanations]] | ||
Revision as of 10:52, 10 October 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: ^^^Michael Suits^^^ and ^^^Wade Abbott^^^
- Responsible Curator: ^^^Spencer Williams^^^
Introduction
Polysaccharide lyases (PLs) cleave uronic acid-containing polysaccharides via a β-elimination mechanism to generate an unsaturated hexenuronic acid residue and a new reducing end at the point of cleavage [1, 2]. PLs have been grouped into families and subfamilies within the Carbohydrate-Active Enzyme (CAZy) framework and that the PLs included are restricted to those operating via syn- and anti-elimination mechanisms [1]. In this way, they are distinct from carbon-oxygen lyases that modify polysaccharide composition. Broadly, the mechanism of PL action can be described as consisting of three events: (i) abstraction of the C-5 proton on the sugar ring of a uronic acid or ester by a charge stabilizing cation such as Ca2+ or a basic amino acid side chain, (ii) stabilization of the resulting anion by charge delocalization onto the C-6 carbonyl group, and (iii) lytic cleavage of the O-4:C-4 bonding that is facilitated by proton donation from a catalytic acid [1, 3]. Please see the following reviews on PL classification, specificities, mechanisms, and structures [1, 2, 3, 4].
References
- Lombard V, Bernard T, Rancurel C, Brumer H, Coutinho PM, and Henrissat B. (2010). A hierarchical classification of polysaccharide lyases for glycogenomics. Biochem J. 2010;432(3):437-44. DOI:10.1042/BJ20101185 |
- Garron ML and Cygler M. (2010). Structural and mechanistic classification of uronic acid-containing polysaccharide lyases. Glycobiology. 2010;20(12):1547-73. DOI:10.1093/glycob/cwq122 |
- Yip VL and Withers SG. (2006). Breakdown of oligosaccharides by the process of elimination. Curr Opin Chem Biol. 2006;10(2):147-55. DOI:10.1016/j.cbpa.2006.02.005 |
- Garron ML and Cygler M. (2014). Uronic polysaccharide degrading enzymes. Curr Opin Struct Biol. 2014;28:87-95. DOI:10.1016/j.sbi.2014.07.012 |