1v02
From Proteopedia
(New page: 200px<br /><applet load="1v02" size="450" color="white" frame="true" align="right" spinBox="true" caption="1v02, resolution 1.80Å" /> '''CRYSTAL STRUCTURE OF...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:1v02.gif|left|200px]]<br /><applet load="1v02" size=" | + | [[Image:1v02.gif|left|200px]]<br /><applet load="1v02" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1v02, resolution 1.80Å" /> | caption="1v02, resolution 1.80Å" /> | ||
'''CRYSTAL STRUCTURE OF THE SORGHUM BICOLOR DHURRINASE 1'''<br /> | '''CRYSTAL STRUCTURE OF THE SORGHUM BICOLOR DHURRINASE 1'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Plant beta-glucosidases play a crucial role in defense against pests. They | + | Plant beta-glucosidases play a crucial role in defense against pests. They cleave, with variable specificity, beta-glucosides to release toxic aglycone moieties. The Sorghum bicolor beta-glucosidase isoenzyme Dhr1 has a strict specificity for its natural substrate dhurrin (p-hydroxy-(S)-mandelonitrile-beta-D-glucoside), whereas its close homolog, the maize beta-glucosidase isoenzyme Glu1, which shares 72% sequence identity, hydrolyzes a broad spectrum of substrates in addition to its natural substrate 2-O-beta-D-glucopyranosyl-4-hydroxy-7-methoxy-1,4-benzoxaxin-3-one. Structural data from enzyme.substrate complexes of Dhr1 show that the mode of aglycone binding differs from that previously observed in the homologous maize enzyme. Specifically, the data suggest that Asn(259), Phe(261), and Ser(462), located in the aglycone-binding site of S. bicolor Dhr1, are crucial for aglycone recognition and binding. The tight binding of the aglycone moiety of dhurrin promotes the stabilization of the reaction intermediate in which the glycone moiety is in a deformed (1)S(3) conformation within the glycone-binding site, ready for nucleophilic attack to occur. Compared with the broad specificity maize beta-glucosidase, this different binding mode explains the narrow specificity of sorghum dhurrinase-1. |
==About this Structure== | ==About this Structure== | ||
| - | 1V02 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Sorghum_bicolor Sorghum bicolor]. Active as [http://en.wikipedia.org/wiki/Beta-glucosidase Beta-glucosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.21 3.2.1.21] Full crystallographic information is available from [http:// | + | 1V02 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Sorghum_bicolor Sorghum bicolor]. Active as [http://en.wikipedia.org/wiki/Beta-glucosidase Beta-glucosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.21 3.2.1.21] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1V02 OCA]. |
==Reference== | ==Reference== | ||
| Line 14: | Line 14: | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Sorghum bicolor]] | [[Category: Sorghum bicolor]] | ||
| - | [[Category: Bevan, D | + | [[Category: Bevan, D R.]] |
[[Category: Czjzek, M.]] | [[Category: Czjzek, M.]] | ||
[[Category: Esen, A.]] | [[Category: Esen, A.]] | ||
| Line 26: | Line 26: | ||
[[Category: pest defense]] | [[Category: pest defense]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:30:10 2008'' |
Revision as of 13:30, 21 February 2008
|
CRYSTAL STRUCTURE OF THE SORGHUM BICOLOR DHURRINASE 1
Overview
Plant beta-glucosidases play a crucial role in defense against pests. They cleave, with variable specificity, beta-glucosides to release toxic aglycone moieties. The Sorghum bicolor beta-glucosidase isoenzyme Dhr1 has a strict specificity for its natural substrate dhurrin (p-hydroxy-(S)-mandelonitrile-beta-D-glucoside), whereas its close homolog, the maize beta-glucosidase isoenzyme Glu1, which shares 72% sequence identity, hydrolyzes a broad spectrum of substrates in addition to its natural substrate 2-O-beta-D-glucopyranosyl-4-hydroxy-7-methoxy-1,4-benzoxaxin-3-one. Structural data from enzyme.substrate complexes of Dhr1 show that the mode of aglycone binding differs from that previously observed in the homologous maize enzyme. Specifically, the data suggest that Asn(259), Phe(261), and Ser(462), located in the aglycone-binding site of S. bicolor Dhr1, are crucial for aglycone recognition and binding. The tight binding of the aglycone moiety of dhurrin promotes the stabilization of the reaction intermediate in which the glycone moiety is in a deformed (1)S(3) conformation within the glycone-binding site, ready for nucleophilic attack to occur. Compared with the broad specificity maize beta-glucosidase, this different binding mode explains the narrow specificity of sorghum dhurrinase-1.
About this Structure
1V02 is a Protein complex structure of sequences from Sorghum bicolor. Active as Beta-glucosidase, with EC number 3.2.1.21 Full crystallographic information is available from OCA.
Reference
Structural determinants of substrate specificity in family 1 beta-glucosidases: novel insights from the crystal structure of sorghum dhurrinase-1, a plant beta-glucosidase with strict specificity, in complex with its natural substrate., Verdoucq L, Moriniere J, Bevan DR, Esen A, Vasella A, Henrissat B, Czjze M, J Biol Chem. 2004 Jul 23;279(30):31796-803. Epub 2004 May 17. PMID:15148317
Page seeded by OCA on Thu Feb 21 15:30:10 2008
