1qmj
From Proteopedia
(New page: 200px<br /><applet load="1qmj" size="450" color="white" frame="true" align="right" spinBox="true" caption="1qmj, resolution 2.15Å" /> '''CG-16, A HOMODIMERIC...) |
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| - | [[Image:1qmj.jpg|left|200px]]<br /><applet load="1qmj" size=" | + | [[Image:1qmj.jpg|left|200px]]<br /><applet load="1qmj" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1qmj, resolution 2.15Å" /> | caption="1qmj, resolution 2.15Å" /> | ||
'''CG-16, A HOMODIMERIC AGGLUTININ FROM CHICKEN LIVER'''<br /> | '''CG-16, A HOMODIMERIC AGGLUTININ FROM CHICKEN LIVER'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Differential developmental regulation of expression, fine-specificity | + | Differential developmental regulation of expression, fine-specificity differences in ligand recognition and disparate capacity for homodimerization are characteristics of the two currently known proto-type chicken galectins. The X-ray crystal structure of the first avian galectin, the homodimeric agglutinin from chicken liver (CG-16), has been solved in the absence of ligand in two crystal forms. Although the arrangement of lectin dimers in the two crystals is different, the structure of the monomers and their association into the extended beta-sandwich that characterises the dimer are virtually identical. The fold establishes a beta-sandwich motif composed of a five-stranded and a six-stranded beta-sheet evocative of proto-type mammalian galectins. The carbohydrate-binding site is occupied by six water molecules that take the place of the sugar in the complex. They help to stabilise in the absence of the ligand the spatial arrangement of the amino acid side-chains involved in sugar recognition. Docking of N-acetyllactosamine into the binding site reveals that three of these water molecules, which are in direct contact with the protein, occupy positions equivalent to the key sugar hydroxyl groups, namely the hydroxyls at positions 4 and 6 of the galactose unit and at position 3 of the N-acetylglucosamine unit. Crystallographic data are fully consistent with the binding features in solution previously derived from chemical mapping with deoxy, fluoro and O-methyl derivatives and laser photo-CIDNP (chemically induced dynamic nuclear polarisation) studies. The possible molecular basis for the monomeric character of the chicken intestinal galectin as well as potential mechanisms of oxidative inactivation by disulphide bridging are evaluated on the basis of the given structural information concerning the CG-16 dimer interface and the cysteine residues, respectively. |
==About this Structure== | ==About this Structure== | ||
| - | 1QMJ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus] with BME as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1QMJ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus] with <scene name='pdbligand=BME:'>BME</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QMJ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Diaz-Maurino, T.]] | [[Category: Diaz-Maurino, T.]] | ||
| - | [[Category: Gabius, H | + | [[Category: Gabius, H J.]] |
[[Category: Kaltner, H.]] | [[Category: Kaltner, H.]] | ||
[[Category: Romero, A.]] | [[Category: Romero, A.]] | ||
[[Category: Solis, D.]] | [[Category: Solis, D.]] | ||
| - | [[Category: Varela, P | + | [[Category: Varela, P F.]] |
[[Category: BME]] | [[Category: BME]] | ||
[[Category: galectin]] | [[Category: galectin]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:41:24 2008'' |
Revision as of 12:41, 21 February 2008
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CG-16, A HOMODIMERIC AGGLUTININ FROM CHICKEN LIVER
Overview
Differential developmental regulation of expression, fine-specificity differences in ligand recognition and disparate capacity for homodimerization are characteristics of the two currently known proto-type chicken galectins. The X-ray crystal structure of the first avian galectin, the homodimeric agglutinin from chicken liver (CG-16), has been solved in the absence of ligand in two crystal forms. Although the arrangement of lectin dimers in the two crystals is different, the structure of the monomers and their association into the extended beta-sandwich that characterises the dimer are virtually identical. The fold establishes a beta-sandwich motif composed of a five-stranded and a six-stranded beta-sheet evocative of proto-type mammalian galectins. The carbohydrate-binding site is occupied by six water molecules that take the place of the sugar in the complex. They help to stabilise in the absence of the ligand the spatial arrangement of the amino acid side-chains involved in sugar recognition. Docking of N-acetyllactosamine into the binding site reveals that three of these water molecules, which are in direct contact with the protein, occupy positions equivalent to the key sugar hydroxyl groups, namely the hydroxyls at positions 4 and 6 of the galactose unit and at position 3 of the N-acetylglucosamine unit. Crystallographic data are fully consistent with the binding features in solution previously derived from chemical mapping with deoxy, fluoro and O-methyl derivatives and laser photo-CIDNP (chemically induced dynamic nuclear polarisation) studies. The possible molecular basis for the monomeric character of the chicken intestinal galectin as well as potential mechanisms of oxidative inactivation by disulphide bridging are evaluated on the basis of the given structural information concerning the CG-16 dimer interface and the cysteine residues, respectively.
About this Structure
1QMJ is a Single protein structure of sequence from Gallus gallus with as ligand. Full crystallographic information is available from OCA.
Reference
The 2.15 A crystal structure of CG-16, the developmentally regulated homodimeric chicken galectin., Varela PF, Solis D, Diaz-Maurino T, Kaltner H, Gabius HJ, Romero A, J Mol Biol. 1999 Nov 26;294(2):537-49. PMID:10610778
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