1jot: Difference between revisions
New page: left|200px<br /><applet load="1jot" size="450" color="white" frame="true" align="right" spinBox="true" caption="1jot, resolution 2.20Å" /> '''STRUCTURE OF THE LEC... |
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[[Image:1jot.gif|left|200px]]<br /><applet load="1jot" size=" | [[Image:1jot.gif|left|200px]]<br /><applet load="1jot" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1jot, resolution 2.20Å" /> | caption="1jot, resolution 2.20Å" /> | ||
'''STRUCTURE OF THE LECTIN MPA COMPLEXED WITH T-ANTIGEN DISACCHARIDE'''<br /> | '''STRUCTURE OF THE LECTIN MPA COMPLEXED WITH T-ANTIGEN DISACCHARIDE'''<br /> | ||
==Overview== | ==Overview== | ||
Maclura pomifera agglutinin is a tetrameric plant seed lectin with high | Maclura pomifera agglutinin is a tetrameric plant seed lectin with high affinity for the tumor-associated T-antigen disaccharide, Galbeta1,3GalNAcalpha, and hence for many O-linked glycopeptide structures. Unlike members of most lectin families, it lacks both metal ions and Cys residues. The structure of its complex with Galbeta1,3GalNAc was determined to 2.2 by first using multiwavelength anomalous diffraction with a lead derivative of the native protein, and then using molecular replacement with the unrefined structure as a model to solve the structure of the complex. The subunits share the beta-prism architecture and three-fold pseudo-symmetry of the related lectin jacalin, with the 21-residue beta-chains in the center of the tetramer. Interactions with the GalNAc predominate in the binding of the disaccharide. It forms a network of H-bonds with only one side chain, from an Asp residue, the amino group of the N-terminal Gly of the alpha-chain, and peptide backbone atoms of two aromatic residues. The Gal moiety does not H-bond directly with residues in the same monomer, i.e. there is no true subsite for it, but there are interactions through two water molecules. In the crystal, it interacts with residues in the binding site of an adjacent tetramer. The minimum energy conformation expected for the disaccharide is retained, despite its mediating the tetramer-tetramer interactions in the crystal packing. The resulting lattice is comparable to those seen for complexes of other lectins with branched glycopeptides. | ||
==About this Structure== | ==About this Structure== | ||
1JOT is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Maclura_pomifera Maclura pomifera]. Full crystallographic information is available from [http:// | 1JOT is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Maclura_pomifera Maclura pomifera]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JOT OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Biesterfeldt, J.]] | [[Category: Biesterfeldt, J.]] | ||
[[Category: Hoa, T | [[Category: Hoa, T T.]] | ||
[[Category: Johnston, R | [[Category: Johnston, R A.Z.]] | ||
[[Category: Lee, X.]] | [[Category: Lee, X.]] | ||
[[Category: Ogata, C.]] | [[Category: Ogata, C.]] | ||
[[Category: Thompson, A.]] | [[Category: Thompson, A.]] | ||
[[Category: Xu, L.]] | [[Category: Xu, L.]] | ||
[[Category: Young, N | [[Category: Young, N M.]] | ||
[[Category: Zhang, Z.]] | [[Category: Zhang, Z.]] | ||
[[Category: beta prism]] | [[Category: beta prism]] | ||
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[[Category: t-antigen]] | [[Category: t-antigen]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:25:00 2008'' | ||
Revision as of 14:25, 21 February 2008
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STRUCTURE OF THE LECTIN MPA COMPLEXED WITH T-ANTIGEN DISACCHARIDE
OverviewOverview
Maclura pomifera agglutinin is a tetrameric plant seed lectin with high affinity for the tumor-associated T-antigen disaccharide, Galbeta1,3GalNAcalpha, and hence for many O-linked glycopeptide structures. Unlike members of most lectin families, it lacks both metal ions and Cys residues. The structure of its complex with Galbeta1,3GalNAc was determined to 2.2 by first using multiwavelength anomalous diffraction with a lead derivative of the native protein, and then using molecular replacement with the unrefined structure as a model to solve the structure of the complex. The subunits share the beta-prism architecture and three-fold pseudo-symmetry of the related lectin jacalin, with the 21-residue beta-chains in the center of the tetramer. Interactions with the GalNAc predominate in the binding of the disaccharide. It forms a network of H-bonds with only one side chain, from an Asp residue, the amino group of the N-terminal Gly of the alpha-chain, and peptide backbone atoms of two aromatic residues. The Gal moiety does not H-bond directly with residues in the same monomer, i.e. there is no true subsite for it, but there are interactions through two water molecules. In the crystal, it interacts with residues in the binding site of an adjacent tetramer. The minimum energy conformation expected for the disaccharide is retained, despite its mediating the tetramer-tetramer interactions in the crystal packing. The resulting lattice is comparable to those seen for complexes of other lectins with branched glycopeptides.
About this StructureAbout this Structure
1JOT is a Protein complex structure of sequences from Maclura pomifera. Full crystallographic information is available from OCA.
ReferenceReference
Structure of the complex of Maclura pomifera agglutinin and the T-antigen disaccharide, Galbeta1,3GalNAc., Lee X, Thompson A, Zhang Z, Ton-that H, Biesterfeldt J, Ogata C, Xu L, Johnston RA, Young NM, J Biol Chem. 1998 Mar 13;273(11):6312-8. PMID:9497359
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