1bxh
From Proteopedia
(New page: 200px<br /><applet load="1bxh" size="450" color="white" frame="true" align="right" spinBox="true" caption="1bxh, resolution 2.75Å" /> '''CONCANAVALIN A COMPL...) |
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| - | [[Image:1bxh.jpg|left|200px]]<br /><applet load="1bxh" size=" | + | [[Image:1bxh.jpg|left|200px]]<br /><applet load="1bxh" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1bxh, resolution 2.75Å" /> | caption="1bxh, resolution 2.75Å" /> | ||
'''CONCANAVALIN A COMPLEXED TO METHYL ALPHA1-2 MANNOBIOSIDE'''<br /> | '''CONCANAVALIN A COMPLEXED TO METHYL ALPHA1-2 MANNOBIOSIDE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | We have determined the crystal structure of the methyl glycoside of Man | + | We have determined the crystal structure of the methyl glycoside of Man alpha1-2 Man in complex with the carbohydrate binding legume lectin concanavalin A (Con A). Man alpha1-2 Man alpha-OMe binds more tightly to concanavalin A than do its alpha1-3 and alpha1-6 linked counterparts. There has been much speculation as to why this is so, including a suggestion of the presence of multiple binding sites for the alpha1-2 linked disaccharide. Crystals of the Man alpha1-2 Man alpha-OMe-Con A complex form in the space group P2(1)2(1)2(1) with cell dimensions a = 119.7 A, b = 119.7 A, c = 68.9 A and diffract to 2. 75A. The final model has good geometry and an R factor of 19.6% (Rfree= 22.8%). One tetramer is present in the asymmetric unit. In three of the four subunits, electron density for the disaccharide is visible. In the fourth only a monosaccharide is seen. In one subunit the reducing terminal sugar is recognized by the monosaccharide site; the nonreducing terminal sugar occupies a new site and the major solution conformation of the inter-sugar glycosidic linkage conformation is adopted. In contrast, in another subunit the non reducing terminal sugar sits in the so called monosaccharide binding site; the reducing terminal sugar adopts a different conformation about its inter-sugar glycosidic linkage in order for the methyl group to access a hydrophobic pocket. In the third subunit, electron density for both binding modes is observed. We demonstrate that an extended carbohydrate binding site is capable of binding the disaccharide in two distinct ways. These results provide an insight in to the balance of forces controlling protein carbohydrate interactions. |
==About this Structure== | ==About this Structure== | ||
| - | 1BXH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Canavalia_ensiformis Canavalia ensiformis] with MMA, MN and CA as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1BXH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Canavalia_ensiformis Canavalia ensiformis] with <scene name='pdbligand=MMA:'>MMA</scene>, <scene name='pdbligand=MN:'>MN</scene> and <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1BXH OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Canaan, B.]] | [[Category: Canaan, B.]] | ||
| - | [[Category: Field, R | + | [[Category: Field, R A.]] |
| - | [[Category: Moothoo, D | + | [[Category: Moothoo, D N.]] |
| - | [[Category: Naismith, J | + | [[Category: Naismith, J H.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: MMA]] | [[Category: MMA]] | ||
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[[Category: thermodynamics]] | [[Category: thermodynamics]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:00:08 2008'' |
Revision as of 10:00, 21 February 2008
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CONCANAVALIN A COMPLEXED TO METHYL ALPHA1-2 MANNOBIOSIDE
Overview
We have determined the crystal structure of the methyl glycoside of Man alpha1-2 Man in complex with the carbohydrate binding legume lectin concanavalin A (Con A). Man alpha1-2 Man alpha-OMe binds more tightly to concanavalin A than do its alpha1-3 and alpha1-6 linked counterparts. There has been much speculation as to why this is so, including a suggestion of the presence of multiple binding sites for the alpha1-2 linked disaccharide. Crystals of the Man alpha1-2 Man alpha-OMe-Con A complex form in the space group P2(1)2(1)2(1) with cell dimensions a = 119.7 A, b = 119.7 A, c = 68.9 A and diffract to 2. 75A. The final model has good geometry and an R factor of 19.6% (Rfree= 22.8%). One tetramer is present in the asymmetric unit. In three of the four subunits, electron density for the disaccharide is visible. In the fourth only a monosaccharide is seen. In one subunit the reducing terminal sugar is recognized by the monosaccharide site; the nonreducing terminal sugar occupies a new site and the major solution conformation of the inter-sugar glycosidic linkage conformation is adopted. In contrast, in another subunit the non reducing terminal sugar sits in the so called monosaccharide binding site; the reducing terminal sugar adopts a different conformation about its inter-sugar glycosidic linkage in order for the methyl group to access a hydrophobic pocket. In the third subunit, electron density for both binding modes is observed. We demonstrate that an extended carbohydrate binding site is capable of binding the disaccharide in two distinct ways. These results provide an insight in to the balance of forces controlling protein carbohydrate interactions.
About this Structure
1BXH is a Single protein structure of sequence from Canavalia ensiformis with , and as ligands. Full crystallographic information is available from OCA.
Reference
Man alpha1-2 Man alpha-OMe-concanavalin A complex reveals a balance of forces involved in carbohydrate recognition., Moothoo DN, Canan B, Field RA, Naismith JH, Glycobiology. 1999 Jun;9(6):539-45. PMID:10336986
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