View source for 4ax6


==HYPOCREA JECORINA CEL6A D221A MUTANT SOAKED WITH 6-CHLORO-4- PHENYLUMBELLIFERYL-BETA-CELLOBIOSIDE==
<StructureSection load='4ax6' size='340' side='right' caption='[[4ax6]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4ax6]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Atcc_13631 Atcc 13631]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4AX6 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4AX6 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=BGC:BETA-D-GLUCOSE'>BGC</scene>, <scene name='pdbligand=MAN:ALPHA-D-MANNOSE'>MAN</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=UWU:6-CHLORANYL-7-OXIDANYL-4-PHENYL-CHROMEN-2-ONE'>UWU</scene></td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1cb2|1cb2]], [[1hgw|1hgw]], [[1hgy|1hgy]], [[1qjw|1qjw]], [[1qk0|1qk0]], [[1qk2|1qk2]], [[3cbh|3cbh]], [[4au0|4au0]], [[4ax7|4ax7]]</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Cellulose_1,4-beta-cellobiosidase_(non-reducing_end) Cellulose 1,4-beta-cellobiosidase (non-reducing end)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.91 3.2.1.91] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4ax6 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4ax6 OCA], [http://pdbe.org/4ax6 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4ax6 RCSB], [http://www.ebi.ac.uk/pdbsum/4ax6 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4ax6 ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/GUX2_HYPJE 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. 
<div style="background-color:#fffaf0;">
== 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<ref>PMID:23137336</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4ax6" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Atcc 13631]]
[[Category: Hansson, H]]
[[Category: Ishida, T]]
[[Category: Nerinckx, W]]
[[Category: Piens, K]]
[[Category: Sandgren, M]]
[[Category: Stahlberg, J]]
[[Category: Wu, M]]
[[Category: Cellobiohydrolase]]
[[Category: Cellulase]]
[[Category: Clphufg2]]
[[Category: Fluorogenic substrate]]
[[Category: Gh6]]
[[Category: Glycoprotein]]
[[Category: Glycosidase]]
[[Category: Glycoside hydrolase]]
[[Category: Hydrolase]]