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Difference between revisions of "Glycoside Hydrolase Family 18"
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| Line 12: | Line 12: | ||
|- | |- | ||
|'''Clan''' | |'''Clan''' | ||
| − | |GH- | + | |GH-K |
|- | |- | ||
|'''Mechanism''' | |'''Mechanism''' | ||
| Line 29: | Line 29: | ||
== Substrate specificities == | == Substrate specificities == | ||
| − | + | GH18 is unusual in having both catalytically active chitinase (EC 3.2.1.14) and endo-β-N-acetylglucosaminidases (EC 3.2.1.96) but there are also sub-families of non-hydrolytic proteins that function as carbohydrate binding modules / "lectins" or as xylanase inhibitors. | |
| − | |||
| Line 39: | Line 38: | ||
== Catalytic Residues == | == Catalytic Residues == | ||
| − | + | The catalytically active GH18 enzymes use a double displacement reaction mechanism with "neighbouring group participation". | |
| Line 47: | Line 46: | ||
== Family Firsts == | == Family Firsts == | ||
| − | ;First sterochemistry determination: | + | ;First sterochemistry determination: Often incorrectly reported as inverting, this family performs catalysis with retention of anomeric configuration as first shown on the ''Bacillus ciculans'' enzyme <cite>Armand1994</cite>. |
;First catalytic nucleophile identification: Cite some reference here, with a ''short'' (1-2 senetence) explanation <cite>4</cite>. | ;First catalytic nucleophile identification: Cite some reference here, with a ''short'' (1-2 senetence) explanation <cite>4</cite>. | ||
;First general acid/base residue identification: Cite some reference here, with a ''short'' (1-2 senetence) explanation <cite>2</cite>. | ;First general acid/base residue identification: Cite some reference here, with a ''short'' (1-2 senetence) explanation <cite>2</cite>. | ||
| − | ;First 3-D structure: The first two 3-D structures for GH18 members were the Serratia marcescens chitinase A and the plant defence protein hevamine published "back-to-back" in ''Structure'' in 1994 <cite>Perrakis,ATVA</cite> | + | ;First 3-D structure: The first two 3-D structures for GH18 members were the Serratia marcescens chitinase A and the plant defence protein hevamine published "back-to-back" in ''Structure'' in 1994 <cite>Perrakis,ATVA</cite>. |
== References == | == References == | ||
| Line 57: | Line 56: | ||
#ATVA1 pmid=7704528 | #ATVA1 pmid=7704528 | ||
#AVTA2 pmid=7495789 | #AVTA2 pmid=7495789 | ||
| + | #Armand1994 pmid=8168626 | ||
#3 isbn=978-0-240-52118-3 | #3 isbn=978-0-240-52118-3 | ||
#4 Sinnott, M.L. (1990) Catalytic mechanisms of enzymic glycosyl transfer. Chem. Rev. 90, 1171-1202. [http://dx.doi.org/10.1021/cr00105a006 DOI: 10.1021/cr00105a006] | #4 Sinnott, M.L. (1990) Catalytic mechanisms of enzymic glycosyl transfer. Chem. Rev. 90, 1171-1202. [http://dx.doi.org/10.1021/cr00105a006 DOI: 10.1021/cr00105a006] | ||
Revision as of 04:11, 6 October 2010
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: ^^^Gideon Davies^^^
- Responsible Curator: ^^^Gideon Davies^^^
| Glycoside Hydrolase Family GH18 | |
| Clan | GH-K |
| Mechanism | retaining/inverting |
| Active site residues | known/not known |
| CAZy DB link | |
| http://www.cazy.org/fam/GH18.html | |
Substrate specificities
GH18 is unusual in having both catalytically active chitinase (EC 3.2.1.14) and endo-β-N-acetylglucosaminidases (EC 3.2.1.96) but there are also sub-families of non-hydrolytic proteins that function as carbohydrate binding modules / "lectins" or as xylanase inhibitors.
Kinetics and Mechanism
Content is to be added here.
Catalytic Residues
The catalytically active GH18 enzymes use a double displacement reaction mechanism with "neighbouring group participation".
Three-dimensional structures
Content is to be added here.
Family Firsts
- First sterochemistry determination
- Often incorrectly reported as inverting, this family performs catalysis with retention of anomeric configuration as first shown on the Bacillus ciculans enzyme [1].
- First catalytic nucleophile identification
- Cite some reference here, with a short (1-2 senetence) explanation [2].
- First general acid/base residue identification
- Cite some reference here, with a short (1-2 senetence) explanation [3].
- First 3-D structure
- The first two 3-D structures for GH18 members were the Serratia marcescens chitinase A and the plant defence protein hevamine published "back-to-back" in Structure in 1994 [4, 5].
References
- Armand S, Tomita H, Heyraud A, Gey C, Watanabe T, and Henrissat B. (1994). Stereochemical course of the hydrolysis reaction catalyzed by chitinases A1 and D from Bacillus circulans WL-12. FEBS Lett. 1994;343(2):177-80. DOI:10.1016/0014-5793(94)80314-5 |
-
Sinnott, M.L. (1990) Catalytic mechanisms of enzymic glycosyl transfer. Chem. Rev. 90, 1171-1202. DOI: 10.1021/cr00105a006
- Perrakis A, Tews I, Dauter Z, Oppenheim AB, Chet I, Wilson KS, and Vorgias CE. (1994). Crystal structure of a bacterial chitinase at 2.3 A resolution. Structure. 1994;2(12):1169-80. DOI:10.1016/s0969-2126(94)00119-7 |
- Terwisscha van Scheltinga AC, Kalk KH, Beintema JJ, and Dijkstra BW. (1994). Crystal structures of hevamine, a plant defence protein with chitinase and lysozyme activity, and its complex with an inhibitor. Structure. 1994;2(12):1181-9. DOI:10.1016/s0969-2126(94)00120-0 |
- Terwisscha van Scheltinga AC, Armand S, Kalk KH, Isogai A, Henrissat B, and Dijkstra BW. (1995). Stereochemistry of chitin hydrolysis by a plant chitinase/lysozyme and X-ray structure of a complex with allosamidin: evidence for substrate assisted catalysis. Biochemistry. 1995;34(48):15619-23. DOI:10.1021/bi00048a003 |