1g9g
From Proteopedia
(New page: 200px<br /><applet load="1g9g" size="450" color="white" frame="true" align="right" spinBox="true" caption="1g9g, resolution 1.90Å" /> '''XTAL-STRUCTURE OF TH...) |
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| - | [[Image:1g9g.jpg|left|200px]]<br /><applet load="1g9g" size=" | + | [[Image:1g9g.jpg|left|200px]]<br /><applet load="1g9g" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1g9g, resolution 1.90Å" /> | caption="1g9g, resolution 1.90Å" /> | ||
'''XTAL-STRUCTURE OF THE FREE NATIVE CELLULASE CEL48F'''<br /> | '''XTAL-STRUCTURE OF THE FREE NATIVE CELLULASE CEL48F'''<br /> | ||
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| + | ==Overview== | ||
| + | An efficient breakdown of lignocellulosic biomass is a prerequisite for, the production of second-generation biofuels. Cellulases are key enzymes, in this process. We crystallized complexes between hemithio-cello-deca and, dodecaoses and the inactive mutants E44Q and E55Q of the endo-processive, cellulase Cel48F, one of the most abundant cellulases in cellulosomes from, Clostridium cellulolyticum, to elucidate its processive mechanism. In both, complexes, the cellooligosaccharides occupy similar positions in the, tunnel part of the active site but are more or less buried into the cleft, which hosts the active site. In the E44Q complex, it proceeds along the, upper part of the cavity, while it occupies in the E55Q complex the same, productive binding subsites in the lower part of the cavity that have, previously been reported in Cel48F/cellooligosaccharide complexes. In both, cases, the sugar moieties are stabilized by stacking interactions with, aromatic side chains and H bonds. The upper pathway is gated by Tyr403, which blocks its access in the E55Q complex and offers a new stacking, interaction in the E44Q complex. The new structural data give rise to the, hypothesis of a two-step mechanism in which processive action and chain, disruption occupy different subsites at the end of their trajectory. In, the first part of the mechanism, the chain may smoothly slide up to the, leaving group site along the upper pathway, while in the second part, the, chain is cleaved in the already described productive binding position, located in the lower pathway. The solved native structure of Cel48F, without any bound sugar in the active site confirms the two side-chain, orientations of the proton donor Glu55 as observed in the complex, structures. | ||
==About this Structure== | ==About this Structure== | ||
| - | 1G9G is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Clostridium_cellulolyticum Clostridium cellulolyticum] with CA and MG as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/ | + | 1G9G is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Clostridium_cellulolyticum Clostridium cellulolyticum] with <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=MG:'>MG</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Hydrolase Hydrolase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.4 3.2.1.4] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1G9G OCA]. |
| - | [ | + | |
| + | ==Reference== | ||
| + | Structures of mutants of cellulase Cel48F of Clostridium cellulolyticum in complex with long hemithiocellooligosaccharides give rise to a new view of the substrate pathway during processive action., Parsiegla G, Reverbel C, Tardif C, Driguez H, Haser R, J Mol Biol. 2008 Jan 11;375(2):499-510. Epub 2007 Oct 22. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=18035374 18035374] | ||
[[Category: Clostridium cellulolyticum]] | [[Category: Clostridium cellulolyticum]] | ||
| + | [[Category: Hydrolase]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Belaich, J.P.]] | [[Category: Belaich, J.P.]] | ||
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[[Category: processive-endo]] | [[Category: processive-endo]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jan 23 11:01:13 2008'' |
Revision as of 09:01, 23 January 2008
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XTAL-STRUCTURE OF THE FREE NATIVE CELLULASE CEL48F
Overview
An efficient breakdown of lignocellulosic biomass is a prerequisite for, the production of second-generation biofuels. Cellulases are key enzymes, in this process. We crystallized complexes between hemithio-cello-deca and, dodecaoses and the inactive mutants E44Q and E55Q of the endo-processive, cellulase Cel48F, one of the most abundant cellulases in cellulosomes from, Clostridium cellulolyticum, to elucidate its processive mechanism. In both, complexes, the cellooligosaccharides occupy similar positions in the, tunnel part of the active site but are more or less buried into the cleft, which hosts the active site. In the E44Q complex, it proceeds along the, upper part of the cavity, while it occupies in the E55Q complex the same, productive binding subsites in the lower part of the cavity that have, previously been reported in Cel48F/cellooligosaccharide complexes. In both, cases, the sugar moieties are stabilized by stacking interactions with, aromatic side chains and H bonds. The upper pathway is gated by Tyr403, which blocks its access in the E55Q complex and offers a new stacking, interaction in the E44Q complex. The new structural data give rise to the, hypothesis of a two-step mechanism in which processive action and chain, disruption occupy different subsites at the end of their trajectory. In, the first part of the mechanism, the chain may smoothly slide up to the, leaving group site along the upper pathway, while in the second part, the, chain is cleaved in the already described productive binding position, located in the lower pathway. The solved native structure of Cel48F, without any bound sugar in the active site confirms the two side-chain, orientations of the proton donor Glu55 as observed in the complex, structures.
About this Structure
1G9G is a Single protein structure of sequence from Clostridium cellulolyticum with and as ligands. Active as Hydrolase, with EC number 3.2.1.4 Full crystallographic information is available from OCA.
Reference
Structures of mutants of cellulase Cel48F of Clostridium cellulolyticum in complex with long hemithiocellooligosaccharides give rise to a new view of the substrate pathway during processive action., Parsiegla G, Reverbel C, Tardif C, Driguez H, Haser R, J Mol Biol. 2008 Jan 11;375(2):499-510. Epub 2007 Oct 22. PMID:18035374
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