1afa: Difference between revisions
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|PDB= 1afa |SIZE=350|CAPTION= <scene name='initialview01'>1afa</scene>, resolution 2.0Å | |PDB= 1afa |SIZE=350|CAPTION= <scene name='initialview01'>1afa</scene>, resolution 2.0Å | ||
|SITE= | |SITE= | ||
|LIGAND= <scene name='pdbligand= | |LIGAND= <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=MBG:METHYL-BETA-GALACTOSE'>MBG</scene> | ||
|ACTIVITY= | |ACTIVITY= | ||
|GENE= | |GENE= | ||
|DOMAIN= | |||
|RELATEDENTRY= | |||
|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1afa FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1afa OCA], [http://www.ebi.ac.uk/pdbsum/1afa PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1afa RCSB]</span> | |||
}} | }} | ||
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[[Category: Kolatkar, A R.]] | [[Category: Kolatkar, A R.]] | ||
[[Category: Weis, W I.]] | [[Category: Weis, W I.]] | ||
[[Category: c-type lectin]] | [[Category: c-type lectin]] | ||
[[Category: calcium-binding protein]] | [[Category: calcium-binding protein]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 18:39:06 2008'' | ||
Revision as of 18:39, 30 March 2008
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| , resolution 2.0Å | |||||||
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| Ligands: | , , | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
STRUCTURAL BASIS OF GALACTOSE RECOGNITION IN C-TYPE ANIMAL LECTINS
OverviewOverview
The asialoglycoprotein receptors and many other C-type (Ca2+-dependent) animal lectins specifically recognize galactose- or N-acetylgalactosamine-terminated oligosaccharides. Analogous binding specificity can be engineered into the homologous rat mannose-binding protein A by changing three amino acids and inserting a glycine-rich loop (Iobst, S. T., and Drickamer, K. (1994) J. Biol. Chem. 269, 15512-15519). Crystal structures of this mutant complexed with beta-methyl galactoside and N-acetylgalactosamine (GalNAc) reveal that as with wild-type mannose-binding proteins, the 3- and 4-OH groups of the sugar directly coordinate Ca2+ and form hydrogen bonds with amino acids that also serve as Ca2+ ligands. The different stereochemistry of the 3- and 4-OH groups in mannose and galactose, combined with a fixed Ca2+ coordination geometry, leads to different pyranose ring locations in the two cases. The glycine-rich loop provides selectivity against mannose by holding a critical tryptophan in a position optimal for packing with the apolar face of galactose but incompatible with mannose binding. The 2-acetamido substituent of GalNAc is in the vicinity of amino acid positions identified by site-directed mutagenesis (Iobst, S. T., and Drickamer, K. (1996) J. Biol. Chem. 271, 6686-6693) as being important for the formation of a GalNAc-selective binding site.
About this StructureAbout this Structure
1AFA is a Single protein structure of sequence from Rattus norvegicus. Full crystallographic information is available from OCA.
ReferenceReference
Structural basis of galactose recognition by C-type animal lectins., Kolatkar AR, Weis WI, J Biol Chem. 1996 Mar 22;271(12):6679-85. PMID:8636086
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