1qk0

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(Difference between revisions)

Revision as of 18:47, 27 January 2016

CEL6A (Y169F) WITH A NON-HYDROLYSABLE CELLOTETRAOSE

Structural highlights

1qk0 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:	, , , , , , , ,
Activity:	Cellulose 1,4-beta-cellobiosidase (non-reducing end), with EC number 3.2.1.91
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum

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.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

BACKGROUND: Cel6A is one of the two cellobiohydrolases produced by Trichoderma reesei. The catalytic core has a structure that is a variation of the classic TIM barrel. The active site is located inside a tunnel, the roof of which is formed mainly by a pair of loops. RESULTS: We describe three new ligand complexes. One is the structure of the wild-type enzyme in complex with a nonhydrolysable cello-oligosaccharide, methyl 4-S-beta-cellobiosyl-4-thio-beta-cellobioside (Glc)(2)-S-(Glc)(2), which differs from a cellotetraose in the nature of the central glycosidic linkage where a sulphur atom replaces an oxygen atom. The second structure is a mutant, Y169F, in complex with the same ligand, and the third is the wild-type enzyme in complex with m-iodobenzyl beta-D-glucopyranosyl-beta(1,4)-D-xylopyranoside (IBXG). CONCLUSIONS: The (Glc)(2)-S-(Glc)(2) ligand binds in the -2 to +2 sites in both the wild-type and mutant enzymes. The glucosyl unit in the -1 site is distorted from the usual chair conformation in both structures. The IBXG ligand binds in the -2 to +1 sites, with the xylosyl unit in the -1 site where it adopts the energetically favourable chair conformation. The -1 site glucosyl of the (Glc)(2)-S-(Glc)(2) ligand is unable to take on this conformation because of steric clashes with the protein. The crystallographic results show that one of the tunnel-forming loops in Cel6A is sensitive to modifications at the active site, and is able to take on a number of different conformations. One of the conformational changes disrupts a set of interactions at the active site that we propose is an integral part of the reaction mechanism.

Crystallographic evidence for substrate ring distortion and protein conformational changes during catalysis in cellobiohydrolase Ce16A from trichoderma reesei.,Zou J, Kleywegt GJ, Stahlberg J, Driguez H, Nerinckx W, Claeyssens M, Koivula A, Teeri TT, Jones TA Structure. 1999 Sep 15;7(9):1035-45. PMID:10508787^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Zou J, Kleywegt GJ, Stahlberg J, Driguez H, Nerinckx W, Claeyssens M, Koivula A, Teeri TT, Jones TA. Crystallographic evidence for substrate ring distortion and protein conformational changes during catalysis in cellobiohydrolase Ce16A from trichoderma reesei. Structure. 1999 Sep 15;7(9):1035-45. PMID:10508787

1 Structural highlights
2 Function
3 Evolutionary Conservation
4 Publication Abstract from PubMed
5 See Also
6 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/1qk0"

@@ Line 1: / Line 1: @@
-==CEL6A IN COMPLEX WITH M-IODOBENZYL BETA-D-GLUCOPYRANOSYL-BETA(1,4)-D-XYLOPYRANOSIDE==
+==CEL6A (Y169F) WITH A NON-HYDROLYSABLE CELLOTETRAOSE==
 <StructureSection load='1qk0' size='340' side='right' caption='[[1qk0]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
 == Structural highlights ==
 <table><tr><td colspan='2'>[[1qk0]] 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=1QK0 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1QK0 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=CO:COBALT+(II)+ION'>CO</scene>, <scene name='pdbligand=GLC:ALPHA-D-GLUCOSE'>GLC</scene>, <scene name='pdbligand=IOB:3-IODO-BENZYL+ALCOHOL'>IOB</scene>, <scene name='pdbligand=IOD:IODIDE+ION'>IOD</scene>, <scene name='pdbligand=MAN:ALPHA-D-MANNOSE'>MAN</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=XYS:XYLOPYRANOSE'>XYS</scene>, <scene name='pdbligand=XYP:BETA-D-XYLOPYRANOSE'>XYP</scene></td></tr>
-<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[3cbh|3cbh]], [[1cb2|1cb2]], [[1qjw|1qjw]], [[1qk2|1qk2]]</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=1qk0 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1qk0 OCA], [http://pdbe.org/1qk0 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1qk0 RCSB], [http://www.ebi.ac.uk/pdbsum/1qk0 PDBsum]</span></td></tr>
@@ Line 22: / Line 21: @@
 <div style="background-color:#fffaf0;">
 == Publication Abstract from PubMed ==
-The enzymatic degradation of cellulose is an important process, both ecologically and commercially. The three-dimensional structure of a cellulase, the enzymatic core of CBHII from the fungus Trichoderma reesei reveals an alpha-beta protein with a fold similar to but different from the widely occurring barrel topology first observed in triose phosphate isomerase. The active site of CBHII is located at the carboxyl-terminal end of a parallel beta barrel, in an enclosed tunnel through which the cellulose threads. Two aspartic acid residues, located in the center of the tunnel are the probable catalytic residues.
+BACKGROUND: Cel6A is one of the two cellobiohydrolases produced by Trichoderma reesei. The catalytic core has a structure that is a variation of the classic TIM barrel. The active site is located inside a tunnel, the roof of which is formed mainly by a pair of loops. RESULTS: We describe three new ligand complexes. One is the structure of the wild-type enzyme in complex with a nonhydrolysable cello-oligosaccharide, methyl 4-S-beta-cellobiosyl-4-thio-beta-cellobioside (Glc)(2)-S-(Glc)(2), which differs from a cellotetraose in the nature of the central glycosidic linkage where a sulphur atom replaces an oxygen atom. The second structure is a mutant, Y169F, in complex with the same ligand, and the third is the wild-type enzyme in complex with m-iodobenzyl beta-D-glucopyranosyl-beta(1,4)-D-xylopyranoside (IBXG). CONCLUSIONS: The (Glc)(2)-S-(Glc)(2) ligand binds in the -2 to +2 sites in both the wild-type and mutant enzymes. The glucosyl unit in the -1 site is distorted from the usual chair conformation in both structures. The IBXG ligand binds in the -2 to +1 sites, with the xylosyl unit in the -1 site where it adopts the energetically favourable chair conformation. The -1 site glucosyl of the (Glc)(2)-S-(Glc)(2) ligand is unable to take on this conformation because of steric clashes with the protein. The crystallographic results show that one of the tunnel-forming loops in Cel6A is sensitive to modifications at the active site, and is able to take on a number of different conformations. One of the conformational changes disrupts a set of interactions at the active site that we propose is an integral part of the reaction mechanism.
-Three-dimensional structure of cellobiohydrolase II from Trichoderma reesei.,Rouvinen J, Bergfors T, Teeri T, Knowles JK, Jones TA Science. 1990 Jul 27;249(4967):380-6. PMID:2377893<ref>PMID:2377893</ref>
+Crystallographic evidence for substrate ring distortion and protein conformational changes during catalysis in cellobiohydrolase Ce16A from trichoderma reesei.,Zou J, Kleywegt GJ, Stahlberg J, Driguez H, Nerinckx W, Claeyssens M, Koivula A, Teeri TT, Jones TA Structure. 1999 Sep 15;7(9):1035-45. PMID:10508787<ref>PMID:10508787</ref>
 From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

1qk0

From Proteopedia

Revision as of 18:47, 27 January 2016

CEL6A (Y169F) WITH A NON-HYDROLYSABLE CELLOTETRAOSE

Structural highlights

Function

Evolutionary Conservation

Publication Abstract from PubMed

See Also

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

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