1ulk
From Proteopedia
(New page: 200px<br /><applet load="1ulk" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ulk, resolution 1.80Å" /> '''Crystal Structure of...) |
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| - | [[Image:1ulk.jpg|left|200px]]<br /><applet load="1ulk" size=" | + | [[Image:1ulk.jpg|left|200px]]<br /><applet load="1ulk" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1ulk, resolution 1.80Å" /> | caption="1ulk, resolution 1.80Å" /> | ||
'''Crystal Structure of Pokeweed Lectin-C'''<br /> | '''Crystal Structure of Pokeweed Lectin-C'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The roots of pokeweed (Phytolacca americana) are known to contain the | + | The roots of pokeweed (Phytolacca americana) are known to contain the lectins designated PL-A, PL-B, PL-C, PL-D1, and PL-D2. Of these lectins, the crystal structures of two PLs, the ligand-free PL-C and the complex of PL-D2 with tri-N-acetylchitotriose, have been determined at 1.8A resolution. The polypeptide chains of PL-C and PL-D2 form three and two repetitive chitin-binding domains, respectively. In the crystal structure of the PL-D2 complex, one trisaccharide molecule is shared mainly between two neighboring molecules related to each other by a crystallographic 2(1)-screw axis, and infinite helical chains of complexed molecules are generated by the sharing of ligand molecules. The crystal structure of PL-C reveals that the molecule is a dimer of two identical subunits, whose polypeptide chains are located in a head-to-tail fashion by a molecular 2-fold axis. Three putative carbohydrate-binding sites in each subunit are located in the dimer interface. The dimerization of PL-C is performed through the hydrophobic interactions between the carbohydrate-binding sites of the opposite domains in the dimer, leading to a distinct dimerization mode from that of wheat-germ agglutinin. Three aromatic residues in each carbohydrate-binding site of PL-C are involved in the dimerization. These residues correspond to the residues that interact mainly with the trisaccharide in the PL-D2 complex and appear to mimic the saccharide residues in the complex. Consequently, the present structure of the PL-C dimer has no room for accommodating carbohydrate. The quaternary structure of PL-C formed through these putative carbohydrate-binding residues may lead to the lack of hemagglutinating activity. |
==About this Structure== | ==About this Structure== | ||
| - | 1ULK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Phytolacca_americana Phytolacca americana]. Full crystallographic information is available from [http:// | + | 1ULK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Phytolacca_americana Phytolacca americana]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ULK OCA]. |
==Reference== | ==Reference== | ||
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[[Category: pl-c]] | [[Category: pl-c]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:25:48 2008'' |
Revision as of 13:25, 21 February 2008
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Crystal Structure of Pokeweed Lectin-C
Overview
The roots of pokeweed (Phytolacca americana) are known to contain the lectins designated PL-A, PL-B, PL-C, PL-D1, and PL-D2. Of these lectins, the crystal structures of two PLs, the ligand-free PL-C and the complex of PL-D2 with tri-N-acetylchitotriose, have been determined at 1.8A resolution. The polypeptide chains of PL-C and PL-D2 form three and two repetitive chitin-binding domains, respectively. In the crystal structure of the PL-D2 complex, one trisaccharide molecule is shared mainly between two neighboring molecules related to each other by a crystallographic 2(1)-screw axis, and infinite helical chains of complexed molecules are generated by the sharing of ligand molecules. The crystal structure of PL-C reveals that the molecule is a dimer of two identical subunits, whose polypeptide chains are located in a head-to-tail fashion by a molecular 2-fold axis. Three putative carbohydrate-binding sites in each subunit are located in the dimer interface. The dimerization of PL-C is performed through the hydrophobic interactions between the carbohydrate-binding sites of the opposite domains in the dimer, leading to a distinct dimerization mode from that of wheat-germ agglutinin. Three aromatic residues in each carbohydrate-binding site of PL-C are involved in the dimerization. These residues correspond to the residues that interact mainly with the trisaccharide in the PL-D2 complex and appear to mimic the saccharide residues in the complex. Consequently, the present structure of the PL-C dimer has no room for accommodating carbohydrate. The quaternary structure of PL-C formed through these putative carbohydrate-binding residues may lead to the lack of hemagglutinating activity.
About this Structure
1ULK is a Single protein structure of sequence from Phytolacca americana. Full crystallographic information is available from OCA.
Reference
Similarity between protein-protein and protein-carbohydrate interactions, revealed by two crystal structures of lectins from the roots of pokeweed., Hayashida M, Fujii T, Hamasu M, Ishiguro M, Hata Y, J Mol Biol. 2003 Nov 28;334(3):551-65. PMID:14623194
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