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Difference between revisions of "Carbohydrate-active enzymes"

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* [[Author]]s: [[User:Steve Withers|Stephen Withers]], [[User:Spencer Williams|Spencer Williams]], and [[User:Harry Brumer|Harry Brumer]]
* [[Author]]: [[User:Withers|Stephen Withers]]
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* [[Responsible Curator]]:  [[User:Spencer Williams|Spencer Williams]]
* [[Responsible Curator]]:  [[User:SpencerWilliams|Spencer Williams]]
 
 
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Carbohydrates collectively are an immensely important group of biomolecules. Individual monosaccharide units have the potential to be joined together to form oligo- and polysaccharides, with the glycosidic linkage occurring between the anomeric position of one sugar with the hydroxyl group of another. Owing ot the many hydroxy groups on each sugar, the potential for two possible anomeric configurations, and the possibility of different ring sizes (pyranose and furanose are the most common), there is a combinatorially-large number of structures possible. Further, carbohydrates can be linked to ther, non-carbohydrate molecules ot generate a wide range of glycoconjugates. Reflecting this structural diversity, there is a large diversity of enzymes involved in the biosynthesis, modification and catabolism of carbohydrates.
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Individual monosaccharide units have the potential to be joined together to form oligo- and polysaccharides, with the glycosidic linkage occurring between the anomeric position of one sugar with the hydroxyl group of another <cite>StickWilliams2009 Sinnott2007</cite>. Owing to the many hydroxy groups on each sugar, the potential for two possible anomeric configurations, and the possibility of different ring sizes (pyranose and furanose are the most common), there is a combinatorially-large number of structures possible <cite>Laine1994</cite>. Further, carbohydrates can be linked to other, non-carbohydrate molecules to generate a wide range of glycoconjugates <cite>TaylorDrickamer2011</cite>. Reflecting this structural diversity, there is a large diversity of enzymes involved in the biosynthesis, modification, binding and catabolism of carbohydrates.
  
The Carbohydrate Active Enzyme classification is a sequence-based classification of enzymes that are active on carbohydrate structures <cite>DaviesSinnott2008 Cantarel2009 Lombard2013</cite>. The creation of a family requires at least one biochemically-characterized member, and is based on the concept that sequence defines protein structure, and protein structure defines function. Generally, but not exclusively, functional properties often extend to other members of the family, and provides a framework upon which to base testable hypotheses of enzyme structure and function.
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==The <U>C</U>arbohydrate <U>A</U>ctive En<U>Zy</U>me ("CAZy") classification==
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The <U>C</U>arbohydrate <U>A</U>ctive En<U>Zy</U>me (CAZy) classification is a [[sequence-based classification]] of enzymes that synthesize or break-down saccharides, which originated with the seminal grouping of glycoside hydrolases by [[User:Bernard Henrissat|Bernard Henrissat]] (<cite>Henrissat1989 Henrissat1991 Henrissat1993 Henrissat1996</cite>; see <cite>DaviesSinnott2008</cite> for a lucid historical review). The creation of a family requires at least one biochemically-characterized member, and is based on the concept that sequence defines protein structure, and protein structure defines function. Generally, but not exclusively, functional properties often extend to other members of the family, and provides a framework upon which to base testable hypotheses of enzyme structure and function <cite>DaviesHenrissat1995</cite>. Since its inception, the CAZy classification and associated database has undergone continually active curation, including the addition of new enzyme and associated module classes <cite>Cantarel2009 Lombard2013 Drula2022</cite>.  Hence, the CAZy classification presently comprises the following modules:
 +
* [[Glycosyltransferase Families]] <cite>Campbell1997 Coutinho2003 Coutinho2009</cite>
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* [[Glycoside Hydrolase Families]] <cite>Henrissat1991 Henrissat1993 Henrissat1996</cite>
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* [[Polysaccharide Lyase Families]] <cite>Lombard2010 Garron2010</cite>
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* [[Carbohydrate Esterase Families]] <cite>Davies2005 Biely2012</cite>
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* [[Auxiliary Activity Families]] <cite>Levasseur2013</cite>
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* [[Carbohydrate Binding Module Families]] (non-catalytic; included due to their association with catalytic modules) <cite>Cantarel2009</cite>. 
  
The major classes of carbohydrate active enzymes within the CAZy classification are:
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Further information on the composition of the families and mechanistic details can be obtained via these pages and the corresponding [[Lexicon]] entries.
 
 
==Glycoside hydrolases (GH)==
 
Strictly speaking, the term '[[glycoside hydrolase]]' or 'glycosidase' refers to enzymes that catalyze the hydrolytic cleavage of the glycosidic bond to give the carbohydrate hemiacetal. However, it is found that sequence-based classification methods often group in enzymes that have non-hydrolytic activities into the same families as hydrolytic enzymes.
 
 
 
* [[Transglycosidases]]: Sequence analysis groups [[transglycosidases]] with [[retaining]] [[glycoside hydrolases]]. According to all available evidence[[transglycosidases]] and [[glycoside hydrolases]] use the same mechanism, except that a sugar or some other group, rather than water, acts as the nucleophile.
 
 
 
* Phosphorylases]]: Sequence similarly groups many, but all (see Glycosyltransferases, below) [[phosphorylases]] with [[retaining]] and [[inverting]] [[glycoside hydrolases]]. Enzymatic cleavage of the bond between two sugars or between a sugar and another group by reaction with phosphate is termed phosphorolysis, and yields the sugar-1-phosphate, and the reaction is reversible, allowing syntehsis of glycosidic linkages form sugar-1-phosphates. Again, GH-like [[phosphorylases]] share mechanistic similarities with [[glycoside hydrolases]].
 
 
 
* [[Alpha-glucan lyases]]: An unusual group of enzymes has been found within family [[GH31]] termed [[alpha-glucan lyases]] that degrade starch via an elimination mechanism, rather than via hydrolysis, forming an unsaturated (enol) product that tautomerises to its keto form, 1,5-anhydro fructose. Again, there are mechanistic similarities between [[alpha-glucan lyases and [[glycoside hydrolases]].
 
 
 
* [[NAD-dependent hydrolysis|NAD-dependent glycoside hydrolases]]: Another unusual group of enzymes use an NAD-cofactor to hydrolyze through a mechanism involving a redox reaction. These enzymes are found within familes [[GH4]] and [[GH109]].
 
 
 
==Polysaccharide lyases (PL)==
 
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. These enzymes are distinct from [[alpha-glucan lyases]], which are classified within the GH modules, as described above.
 
 
 
Key PL classification reviews: <cite>Lombard2010 Garron2010</cite>
 
 
 
==Auxiliary activities (AA)==
 
Key AA ref: <cite>Levasseur2013</cite>
 
 
 
 
 
 
 
==Carbohydrate binding modules (CBM)==
 
Key CBM reviews: <cite>Boraston2004 Shoseyov2006 Hashimoto2006 Guillen2010 Gilbert2013</cite>
 
 
 
==Glycosyltransferases (GT)==
 
The principal enzymes that catalyze glycoside synthesis are nucleotide phosphosugar-dependent ''[[glycosyltransferases]]''.
 
 
 
[[Phosphorylases]] fall into two mechanistic classes: glycoside hydrolase-like and glycosyltransferase-like, and are likewise classified into GH or GT families by sequence comparisons. A second, very small, group of ''[[alpha-glucan lyases]]'' is found within [[Glycoside Hydrolase Family 31|GH Family 31]] and follows a cationic glycoside-hydrolase-like mechanism.
 
 
 
Key GT review: <cite>Lairson2008</cite>
 
  
 
== References ==
 
== References ==
 
<biblio>
 
<biblio>
#DaviesSinnott2008 Davies, G.J. and Sinnott, M.L. (2008) Sorting the diverse: the sequence-based classifications of carbohydrate-active enzymes. ''Biochem. J.'' (A BJ Classics review, online only). [http://dx.doi.org/10.1042/BJ20080382 DOI: 10.1042/BJ20080382]
+
#StickWilliams2009 isbn=9780240521183
 +
#Laine1994 pmid=7734838
 +
#TaylorDrickamer2011 isbn=9780199569113
 +
#Henrissat1991 pmid=1747104
 +
#Henrissat1993 pmid=8352747
 +
#Henrissat1996 pmid=8687420
 +
#DaviesHenrissat1995 pmid=8535779
 +
#DaviesSinnott2008 Davies, G.J. and Sinnott, M.L. (2008) Sorting the diverse: the sequence-based classifications of carbohydrate-active enzymes. ''The Biochemist'', vol. 30, no. 4., pp. 26-32. [https://doi.org/10.1042/BIO03004026 DOI:10.1042/BIO03004026].
 
#Cantarel2009 pmid=18838391
 
#Cantarel2009 pmid=18838391
 
#Lombard2013 pmid=24270786
 
#Lombard2013 pmid=24270786
#Lairson2008 pmid=18518825
 
 
#Lombard2010 pmid=20925655
 
#Lombard2010 pmid=20925655
 +
#Campbell1997 pmid=9334165
 +
#Coutinho2003 pmid=12691742
 +
#Coutinho2009 isbn=9780470016671 // ''Chapter 5:'' Coutinho PM, Rancurel C, Stam M, Bernard T, Couto FM, Danchin EGJ, Henrissat B. "Carbohydrate-active Enzymes Database: Principles and Classification of Glycosyltransferases."
 
#Garron2010 pmid=20805221
 
#Garron2010 pmid=20805221
 
#Levasseur2013 pmid=23514094
 
#Levasseur2013 pmid=23514094
#Boraston2004 pmid=15214846
+
#Henrissat1989 pmid=2806912
#Shoseyov2006 pmid=16760304
+
#Sinnott2007 isbn=9780854042562
#Hashimoto2006 pmid=17131061
+
#Davies2005 pmid=16263268
#Guillen2010 pmid=19908036
+
#Biely2012 pmid=22580218
#Gilbert2013 pmid=23769966
+
 
#VocadloDavies2008 pmid=18558099
+
#Drula2022 pmid=34850161
#YipWithers2006 pmid=16495121
 
 
</biblio>
 
</biblio>
  
 
[[Category:Definitions and explanations]]
 
[[Category:Definitions and explanations]]

Latest revision as of 11:28, 4 July 2023

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Individual monosaccharide units have the potential to be joined together to form oligo- and polysaccharides, with the glycosidic linkage occurring between the anomeric position of one sugar with the hydroxyl group of another [1, 2]. Owing to the many hydroxy groups on each sugar, the potential for two possible anomeric configurations, and the possibility of different ring sizes (pyranose and furanose are the most common), there is a combinatorially-large number of structures possible [3]. Further, carbohydrates can be linked to other, non-carbohydrate molecules to generate a wide range of glycoconjugates [4]. Reflecting this structural diversity, there is a large diversity of enzymes involved in the biosynthesis, modification, binding and catabolism of carbohydrates.

The Carbohydrate Active EnZyme ("CAZy") classification

The Carbohydrate Active EnZyme (CAZy) classification is a sequence-based classification of enzymes that synthesize or break-down saccharides, which originated with the seminal grouping of glycoside hydrolases by Bernard Henrissat ([5, 6, 7, 8]; see [9] for a lucid historical review). The creation of a family requires at least one biochemically-characterized member, and is based on the concept that sequence defines protein structure, and protein structure defines function. Generally, but not exclusively, functional properties often extend to other members of the family, and provides a framework upon which to base testable hypotheses of enzyme structure and function [10]. Since its inception, the CAZy classification and associated database has undergone continually active curation, including the addition of new enzyme and associated module classes [11, 12, 13]. Hence, the CAZy classification presently comprises the following modules:

Further information on the composition of the families and mechanistic details can be obtained via these pages and the corresponding Lexicon entries.

References

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  1. Robert V. Stick and Spencer J. Williams. (2009) Carbohydrates. Elsevier Science. [StickWilliams2009]
  2. Michael Sinnott. (2007) Carbohydrate Chemistry and Biochemistry. Royal Society of Chemistry. [Sinnott2007]
  3. Error fetching PMID 7734838: [Laine1994]
  4. Maureen E. Taylor and Kurt Drickamer. (2011-04-21) Introduction to Glycobiology. [TaylorDrickamer2011]
  5. Error fetching PMID 2806912: [Henrissat1989]
  6. Henrissat B (1991). A classification of glycosyl hydrolases based on amino acid sequence similarities. Biochem J. 1991;280 ( Pt 2)(Pt 2):309-16. DOI:10.1042/bj2800309 | PubMed ID:1747104 [Henrissat1991]
  7. Error fetching PMID 8352747: [Henrissat1993]
  8. Henrissat B and Bairoch A. (1996). Updating the sequence-based classification of glycosyl hydrolases. Biochem J. 1996;316 ( Pt 2)(Pt 2):695-6. DOI:10.1042/bj3160695 | PubMed ID:8687420 [Henrissat1996]
  9. Davies, G.J. and Sinnott, M.L. (2008) Sorting the diverse: the sequence-based classifications of carbohydrate-active enzymes. The Biochemist, vol. 30, no. 4., pp. 26-32. DOI:10.1042/BIO03004026.

    [DaviesSinnott2008]
  10. Davies G and Henrissat B. (1995). Structures and mechanisms of glycosyl hydrolases. Structure. 1995;3(9):853-9. DOI:10.1016/S0969-2126(01)00220-9 | PubMed ID:8535779 [DaviesHenrissat1995]
  11. 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 | PubMed ID:18838391 [Cantarel2009]
  12. Error fetching PMID 24270786: [Lombard2013]
  13. Error fetching PMID 34850161: [Drula2022]
  14. Error fetching PMID 9334165: [Campbell1997]
  15. Error fetching PMID 12691742: [Coutinho2003]
  16. Claus-Wilhelm von der Lieth, Thomas Luetteke, and Martin Frank. (2010-01-19) Bioinformatics for Glycobiology and Glycomics: An Introduction. Wiley. [Coutinho2009]

    Chapter 5: Coutinho PM, Rancurel C, Stam M, Bernard T, Couto FM, Danchin EGJ, Henrissat B. "Carbohydrate-active Enzymes Database: Principles and Classification of Glycosyltransferases."

  17. 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 | PubMed ID:20925655 [Lombard2010]
  18. Error fetching PMID 20805221: [Garron2010]
  19. Error fetching PMID 16263268: [Davies2005]
  20. Error fetching PMID 22580218: [Biely2012]
  21. Error fetching PMID 23514094: [Levasseur2013]

All Medline abstracts: PubMed