1lem
From Proteopedia
(New page: 200px<br /><applet load="1lem" size="450" color="white" frame="true" align="right" spinBox="true" caption="1lem, resolution 3.0Å" /> '''THE MONOSACCHARIDE BI...) |
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| - | [[Image:1lem.gif|left|200px]]<br /><applet load="1lem" size=" | + | [[Image:1lem.gif|left|200px]]<br /><applet load="1lem" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1lem, resolution 3.0Å" /> | caption="1lem, resolution 3.0Å" /> | ||
'''THE MONOSACCHARIDE BINDING SITE OF LENTIL LECTIN: AN X-RAY AND MOLECULAR MODELLING STUDY'''<br /> | '''THE MONOSACCHARIDE BINDING SITE OF LENTIL LECTIN: AN X-RAY AND MOLECULAR MODELLING STUDY'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The X-ray crystal structure of lentil lectin in complex with | + | The X-ray crystal structure of lentil lectin in complex with alpha-D-glucopyranose has been determined by molecular replacement and refined to an R-value of 0.20 at 3.0 A resolution. The glucose interacts with the protein in a manner similar to that found in the mannose complexes of concanavalin A, pea lectin and isolectin I from Lathyrus ochrus. The complex is stabilized by a network of hydrogen bonds involving the carbohydrate oxygens O6, O4, O3 and O5. In addition, the alpha-D-glucopyranose residue makes van der Waals contacts with the protein, involving the phenyl ring of Phe123 beta. The overall structure of lentil lectin, at this resolution, does not differ significantly from the highly refined structures of the uncomplexed lectin. Molecular docking studies were performed with mannose and its 2-O and 3-O-m-nitro-benzyl derivatives to explain their high affinity binding. The interactions of the modelled mannose with lentil lectin agree well with those observed experimentally for the protein-carbohydrate complex. The highly flexible Me-2-O-(m-nitro-benzyl)-alpha-D-mannopyranoside and Me-3-O-(m-nitro-benzyl)-alpha-D-mannopyranoside become conformationally restricted upon binding to lentil lectin. For best orientations of the two substrates in the combining site, the loss of entropy is accompanied by the formation of a strong hydrogen bond between the nitro group and one amino acid, Gly97 beta and Asn125 beta, respectively, along with the establishment of van der Waals interactions between the benzyl group and the aromatic amino acids Tyr100 beta and Trp128 beta. |
==About this Structure== | ==About this Structure== | ||
| - | 1LEM is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Lens_culinaris Lens culinaris] with GLC, CA and MN as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1LEM is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Lens_culinaris Lens culinaris] with <scene name='pdbligand=GLC:'>GLC</scene>, <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=MN:'>MN</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LEM OCA]. |
==Reference== | ==Reference== | ||
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[[Category: lectin]] | [[Category: lectin]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:44:15 2008'' |
Revision as of 11:44, 21 February 2008
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THE MONOSACCHARIDE BINDING SITE OF LENTIL LECTIN: AN X-RAY AND MOLECULAR MODELLING STUDY
Overview
The X-ray crystal structure of lentil lectin in complex with alpha-D-glucopyranose has been determined by molecular replacement and refined to an R-value of 0.20 at 3.0 A resolution. The glucose interacts with the protein in a manner similar to that found in the mannose complexes of concanavalin A, pea lectin and isolectin I from Lathyrus ochrus. The complex is stabilized by a network of hydrogen bonds involving the carbohydrate oxygens O6, O4, O3 and O5. In addition, the alpha-D-glucopyranose residue makes van der Waals contacts with the protein, involving the phenyl ring of Phe123 beta. The overall structure of lentil lectin, at this resolution, does not differ significantly from the highly refined structures of the uncomplexed lectin. Molecular docking studies were performed with mannose and its 2-O and 3-O-m-nitro-benzyl derivatives to explain their high affinity binding. The interactions of the modelled mannose with lentil lectin agree well with those observed experimentally for the protein-carbohydrate complex. The highly flexible Me-2-O-(m-nitro-benzyl)-alpha-D-mannopyranoside and Me-3-O-(m-nitro-benzyl)-alpha-D-mannopyranoside become conformationally restricted upon binding to lentil lectin. For best orientations of the two substrates in the combining site, the loss of entropy is accompanied by the formation of a strong hydrogen bond between the nitro group and one amino acid, Gly97 beta and Asn125 beta, respectively, along with the establishment of van der Waals interactions between the benzyl group and the aromatic amino acids Tyr100 beta and Trp128 beta.
About this Structure
1LEM is a Protein complex structure of sequences from Lens culinaris with , and as ligands. Full crystallographic information is available from OCA.
Reference
The monosaccharide binding site of lentil lectin: an X-ray and molecular modelling study., Loris R, Casset F, Bouckaert J, Pletinckx J, Dao-Thi MH, Poortmans F, Imberty A, Perez S, Wyns L, Glycoconj J. 1994 Dec;11(6):507-17. PMID:7696853
Page seeded by OCA on Thu Feb 21 13:44:15 2008
Categories: Lens culinaris | Protein complex | Loris, R. | Wyns, L. | CA | GLC | MN | Lectin
