| Structural highlights
4au0 is a 2 chain structure with sequence from Atcc 13631. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: | , , , |
| Related: | 1cb2, 1hgw, 1hgy, 1qjw, 1qk0, 1qk2, 3cbh, 4ax6, 4ax7 |
| Activity: | Cellulose 1,4-beta-cellobiosidase (non-reducing end), with EC number 3.2.1.91 |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
[GUX2_HYPJE] The biological conversion of cellulose to glucose generally requires three types of hydrolytic enzymes: (1) Endoglucanases which cut internal beta-1,4-glucosidic bonds; (2) Exocellobiohydrolases that cut the dissaccharide cellobiose from the non-reducing end of the cellulose polymer chain; (3) Beta-1,4-glucosidases which hydrolyze the cellobiose and other short cello-oligosaccharides to glucose.
Publication Abstract from PubMed
Methylumbelliferyl-beta-cellobioside (MUF-G2) is a convenient fluorogenic substrate for certain beta-glycoside hydrolases (GH). However, hydrolysis of the aglycone is poor with GH family 6 enzymes (GH6), despite strong binding. Prediction of the orientation of the aglycone of MUF-G2 in the +1 subsite of Hypocrea jecorina Cel6A by automated docking suggested umbelliferyl modifications at C4 and C6 for improved recognition. Four modified umbelliferyl-beta-cellobiosides [6-chloro-4-methyl- (ClMUF); 6-chloro-4-trifluoromethyl- (ClF3MUF); 4-phenyl- (PhUF); 6-chloro-4-phenyl- (ClPhUF)] were synthesized and tested with GH6, GH7, GH9, GH5 and GH45 cellulases. Indeed the rate of aglycone release by H. jecorina Cel6A was 10-150 times higher than with MUF-G2, although it was still three orders of magnitude lower than with H. jecorina Cel7B. The 4-phenyl substitution drastically reduced the fluorescence intensity of the free aglycone, while ClMUF-G2 could be used for determination of k(cat) and K(M) for H. jecorina Cel6A and Thermobifida fusca Cel6A. Crystal structures of H. jecorina Cel6A D221A mutant soaked with the MUF-, ClMUF- and ClPhUF-beta-cellobioside substrates show that the modifications turned the umbelliferyl group 'upside down', with the glycosidic bond better positioned for protonation than with MUF-G2. DATABASE: Structural data have been submitted to the Protein Data Bank under accession numbers pdb 4AU0, 4AX7, 4AX6 STRUCTURED DIGITAL ABSTRACT: * http://mint.bio.uniroma2.it/mint/search/interaction.do?interactionAc=MINT-7260296 * Cel6A and Cel6A bind by x-ray crystallography (View Interaction: 1, 2).
Rational design, synthesis, evaluation and enzyme-substrate structures of improved fluorogenic substrates for family 6 glycoside hydrolases.,Wu M, Nerinckx W, Piens K, Ishida T, Hansson H, Sandgren M, Stahlberg J FEBS J. 2013 Jan;280(1):184-98. doi: 10.1111/febs.12060. Epub 2012 Dec 7. PMID:23137336[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Wu M, Nerinckx W, Piens K, Ishida T, Hansson H, Sandgren M, Stahlberg J. Rational design, synthesis, evaluation and enzyme-substrate structures of improved fluorogenic substrates for family 6 glycoside hydrolases. FEBS J. 2013 Jan;280(1):184-98. doi: 10.1111/febs.12060. Epub 2012 Dec 7. PMID:23137336 doi:http://dx.doi.org/10.1111/febs.12060
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