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Difference between revisions of "Glycoside Hydrolase Family 124"
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== Substrate specificities == | == Substrate specificities == | ||
| − | Family 124 consists of a small number of cellulosomal proteins. The ''Clostridium thermocellum'' enzyme CtCel124A is the only member of this family that has been characterized. The enzyme is an endo-beta1,4-glucanase with modest activity in vitro, but acts in synergy with the major exo-cellulase from ''C. thermocellum'' and, as a discrete entity, is able to deconstruct tobacco cell walls <cite> | + | Family 124 consists of a small number of cellulosomal proteins. The ''Clostridium thermocellum'' enzyme CtCel124A is the only member of this family that has been characterized. The enzyme is an endo-beta1,4-glucanase with modest activity in vitro, but acts in synergy with the major exo-cellulase from ''C. thermocellum'' and, as a discrete entity, is able to deconstruct tobacco cell walls <cite>Bras2011</cite>. |
== Kinetics and Mechanism == | == Kinetics and Mechanism == | ||
| − | HPLC using cellopentaose as the substrate showed that the enzyme has a single displacement inverting mechanism <cite> | + | HPLC using cellopentaose as the substrate showed that the enzyme has a single displacement inverting mechanism <cite>Bras2011</cite>. |
. | . | ||
== Catalytic Residues == | == Catalytic Residues == | ||
| − | + | The catalytic acid in ''Ct''Cel124A was shown to be Glu96 based on the crystal structural of the enzyme and the observation that the Q96A mutation completely inactivates the cellulase <cite>Bras2011</cite>. The enzyme contains no candidate catalytic base and it was suggested that the nucleophilic water was activated by Grotthus”-like mechanism <cite>Koivula2002</cite>. | |
| + | |||
| + | ><cite>Bras2011</cite>. | ||
| + | Bras2011</cite>. | ||
| + | |||
| + | |||
| Line 54: | Line 59: | ||
<biblio> | <biblio> | ||
#Bras2011 pmid=21393568 | #Bras2011 pmid=21393568 | ||
| − | # | + | #Koivula2002 pmid=12188666 |
#StickWilliams isbn=978-0-240-52118-3 | #StickWilliams isbn=978-0-240-52118-3 | ||
#Sinnott1990 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] | #Sinnott1990 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 03:54, 27 April 2012
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: ^^^Harry Gilbert^^^
- Responsible Curator: ^^^Harry Gilbert^^^
| Glycoside Hydrolase Family GH124 | |
| Clan | GH-x |
| Mechanism | retaining/inverting |
| Active site residues | known/not known |
| CAZy DB link | |
| https://www.cazy.org/GH124.html | |
Substrate specificities
Family 124 consists of a small number of cellulosomal proteins. The Clostridium thermocellum enzyme CtCel124A is the only member of this family that has been characterized. The enzyme is an endo-beta1,4-glucanase with modest activity in vitro, but acts in synergy with the major exo-cellulase from C. thermocellum and, as a discrete entity, is able to deconstruct tobacco cell walls [1].
Kinetics and Mechanism
HPLC using cellopentaose as the substrate showed that the enzyme has a single displacement inverting mechanism [1]. .
Catalytic Residues
The catalytic acid in CtCel124A was shown to be Glu96 based on the crystal structural of the enzyme and the observation that the Q96A mutation completely inactivates the cellulase [1]. The enzyme contains no candidate catalytic base and it was suggested that the nucleophilic water was activated by Grotthus”-like mechanism [2].
>[1]. Bras2011.
Three-dimensional structures
Content is to be added here.
Family Firsts
- First stereochemistry determination
- Cite some reference here, with a short (1-2 sentence) explanation [3].
- First catalytic nucleophile identification
- Cite some reference here, with a short (1-2 sentence) explanation [4].
- First general acid/base residue identification
- Cite some reference here, with a short (1-2 sentence) explanation [5].
- First 3-D structure
- Cite some reference here, with a short (1-2 sentence) explanation [6].
References
- Brás JL, Cartmell A, Carvalho AL, Verzé G, Bayer EA, Vazana Y, Correia MA, Prates JA, Ratnaparkhe S, Boraston AB, Romão MJ, Fontes CM, and Gilbert HJ. (2011). Structural insights into a unique cellulase fold and mechanism of cellulose hydrolysis. Proc Natl Acad Sci U S A. 2011;108(13):5237-42. DOI:10.1073/pnas.1015006108 |
- Koivula A, Ruohonen L, Wohlfahrt G, Reinikainen T, Teeri TT, Piens K, Claeyssens M, Weber M, Vasella A, Becker D, Sinnott ML, Zou JY, Kleywegt GJ, Szardenings M, Ståhlberg J, and Jones TA. (2002). The active site of cellobiohydrolase Cel6A from Trichoderma reesei: the roles of aspartic acids D221 and D175. J Am Chem Soc. 2002;124(34):10015-24. DOI:10.1021/ja012659q |
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Sinnott, M.L. (1990) Catalytic mechanisms of enzymic glycosyl transfer. Chem. Rev. 90, 1171-1202. DOI: 10.1021/cr00105a006