1ex1
From Proteopedia
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| - | [[Image:1ex1.gif|left|200px]]<br /> | + | [[Image:1ex1.gif|left|200px]]<br /><applet load="1ex1" size="450" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1ex1" size="450" color="white" frame="true" align="right" spinBox="true" | + | |
caption="1ex1, resolution 2.2Å" /> | caption="1ex1, resolution 2.2Å" /> | ||
'''BETA-D-GLUCAN EXOHYDROLASE FROM BARLEY'''<br /> | '''BETA-D-GLUCAN EXOHYDROLASE FROM BARLEY'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1EX1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Hordeum_vulgare Hordeum vulgare] with NAG and GLC as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Glucan_1,3-beta-glucosidase Glucan 1,3-beta-glucosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.58 3.2.1.58] | + | 1EX1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Hordeum_vulgare Hordeum vulgare] with NAG and GLC as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Glucan_1,3-beta-glucosidase Glucan 1,3-beta-glucosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.58 3.2.1.58] Known structural/functional Site: <scene name='pdbsite=GBS:This Glc Is Bound In The Putative Active Site Of Exo1 Ex ...'>GBS</scene>. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1EX1 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: hydrolase]] | [[Category: hydrolase]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Dec 18 15:13:50 2007'' |
Revision as of 13:04, 18 December 2007
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BETA-D-GLUCAN EXOHYDROLASE FROM BARLEY
Overview
BACKGROUND: Cell walls of the starchy endosperm and young vegetative, tissues of barley (Hordeum vulgare) contain high levels of, (1-->3,1-->4)-beta-D-glucans. The (1-->3,1-->4)-beta-D-glucans are, hydrolysed during wall degradation in germinated grain and during wall, loosening in elongating coleoptiles. These key processes of plant, development are mediated by several polysaccharide endohydrolases and, exohydrolases. RESULTS:. The three-dimensional structure of barley, beta-D-glucan exohydrolase isoenzyme ExoI has been determined by X-ray, crystallography. This is the first reported structure of a family 3, glycosyl hydrolase. The enzyme is a two-domain, globular protein of 605, amino acid residues and is N-glycosylated at three sites. The first 357, residues constitute an (alpha/beta)8 TIM-barrel domain. The second domain, consists of residues 374-559 arranged in a six-stranded beta sandwich, which contains a beta sheet of five parallel beta strands and one, antiparallel beta strand, with three alpha helices on either side of the, sheet. A glucose moiety is observed in a pocket at the interface of the, two domains, where Asp285 and Glu491 are believed to be involved in, catalysis. CONCLUSIONS: The pocket at the interface of the two domains is, probably the active site of the enzyme. Because amino acid residues that, line this active-site pocket arise from both domains, activity could be, regulated through the spatial disposition of the domains. Furthermore, there are sites on the second domain that may bind carbohydrate, as, suggested by previously published kinetic data indicating that, in, addition to the catalytic site, the enzyme has a second binding site, specific for (1-->3, 1-->4)-beta-D-glucans.
About this Structure
1EX1 is a Single protein structure of sequence from Hordeum vulgare with NAG and GLC as ligands. Active as Glucan 1,3-beta-glucosidase, with EC number 3.2.1.58 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of a barley beta-D-glucan exohydrolase, a family 3 glycosyl hydrolase., Varghese JN, Hrmova M, Fincher GB, Structure. 1999 Feb 15;7(2):179-90. PMID:10368285
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