1a78: Difference between revisions

Revision as of 09:55, 2 May 2008

COMPLEX OF TOAD OVARY GALECTIN WITH THIO-DIGALACTOSE

OverviewOverview

Galectin-1, S-type beta-galactosyl-binding lectins present in vertebrate and invertebrate species, are dimeric proteins that participate in cellular adhesion, activation, growth regulation, and apoptosis. Two high-resolution crystal structures of B. arenarum galectin-1 in complex with two related carbohydrates, LacNAc and TDG, show that the topologically equivalent hydroxyl groups in the two disaccharides exhibit identical patterns of interaction with the protein. Groups that are not equivalent between the two sugars present in the second moiety of the disaccharide, interact differently with the protein, but use the same number and quality of interactions. The structures show additional protein-carbohydrate interactions not present in previously reported lectin-lactose complexes. These contacts provide an explanation for the enhanced affinity of galectin-1 for TDG and LacNAc relative to lactose. Galectins are in dimer-monomer equilibrium at physiological protein concentrations, suggesting that this equilibrium may be involved in organ-specific regulation of activity. Comparison of B. arenarum with other galectin-1 structures shows that among different galectins there are significant changes in accessible surface area buried upon dimer formation, providing a rationale for the variations observed in the free-energies of dimerization. The structure of the B. arenarum galectin-1 has a large cleft with a strong negative potential that connects the two binding sites at the surface of the protein. Such a striking characteristic suggests that this cleft is probably involved in interactions of the galectin with other intra or extra-cellular proteins. Proteins 2000;40:378-388.

About this StructureAbout this Structure

1A78 is a Single protein structure of sequence from Bufo arenarum. Full crystallographic information is available from OCA.

ReferenceReference

Soluble beta-galactosyl-binding lectin (galectin) from toad ovary: crystallographic studies of two protein-sugar complexes., Bianchet MA, Ahmed H, Vasta GR, Amzel LM, Proteins. 2000 Aug 15;40(3):378-88. PMID:10861929 Page seeded by OCA on Fri May 2 09:55:09 2008

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OCA

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 [[Image:1a78.jpg|left|200px]]
- {{Structure
+<!--
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+The line below this paragraph, containing "STRUCTURE_1a78", creates the "Structure Box" on the page.
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+You may change the PDB parameter (which sets the PDB file loaded into the applet)
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-|DOMAIN=
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-|RELATEDENTRY=
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1a78 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1a78 OCA], [http://www.ebi.ac.uk/pdbsum/1a78 PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1a78 RCSB]</span>
-}}
 '''COMPLEX OF TOAD OVARY GALECTIN WITH THIO-DIGALACTOSE'''
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 [[Category: Bianchet, M A.]]
 [[Category: Vasta, G R.]]
-[[Category: carbohydrate binding]]
+[[Category: Carbohydrate binding]]
-[[Category: complex (lectin/saccharide)]]
+[[Category: S-lectin]]
-[[Category: s-lectin]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 09:55:09 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 18:34:48 2008''