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New page: left|200px<br /><applet load="1jn2" size="450" color="white" frame="true" align="right" spinBox="true" caption="1jn2, resolution 1.9Å" /> '''Crystal Structure of ...
 
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[[Image:1jn2.jpg|left|200px]]<br /><applet load="1jn2" size="450" color="white" frame="true" align="right" spinBox="true"  
[[Image:1jn2.jpg|left|200px]]<br /><applet load="1jn2" size="350" color="white" frame="true" align="right" spinBox="true"  
caption="1jn2, resolution 1.9&Aring;" />
caption="1jn2, resolution 1.9&Aring;" />
'''Crystal Structure of meso-tetrasulphonatophenyl porphyrin complexed with Concanavalin A'''<br />
'''Crystal Structure of meso-tetrasulphonatophenyl porphyrin complexed with Concanavalin A'''<br />


==Overview==
==Overview==
The crystal structure of meso-tetrasulfonatophenylporphyrin complexed with, concanavalin A (ConA) was determined at 1.9 A resolution. Comparison of, this structure with that of ConA bound to methyl alpha-d-mannopyranoside, provided direct structural evidence of molecular mimicry in the context of, ligand receptor binding. The sulfonatophenyl group of, meso-tetrasulfonatophenylporphyrin occupies the same binding site on ConA, as that of methyl alpha-d-mannopyranoside, a natural ligand. A pair of, stacked porphyrin molecules stabilizes the crystal structure by end-to-end, cross-linking with ConA resulting in a network similar to that observed, upon agglutination of cells by lectins. The porphyrin binds to ConA, predominantly through hydrogen bonds and water-mediated interactions. The, sandwiched water molecules in the complex play a cementing role, facilitating favorable binding of porphyrin. Seven of the eight hydrogen, bonds observed between methyl alpha-d-mannopyranoside and ConA are, mimicked by the sulfonatophenyl group of porphyrin after incorporating two, water molecules. Thus, the similarity in chemical interactions was, manifested in terms of functional mimicry despite the obvious structural, dissimilarity between the sugar and the porphyrin.
The crystal structure of meso-tetrasulfonatophenylporphyrin complexed with concanavalin A (ConA) was determined at 1.9 A resolution. Comparison of this structure with that of ConA bound to methyl alpha-d-mannopyranoside provided direct structural evidence of molecular mimicry in the context of ligand receptor binding. The sulfonatophenyl group of meso-tetrasulfonatophenylporphyrin occupies the same binding site on ConA as that of methyl alpha-d-mannopyranoside, a natural ligand. A pair of stacked porphyrin molecules stabilizes the crystal structure by end-to-end cross-linking with ConA resulting in a network similar to that observed upon agglutination of cells by lectins. The porphyrin binds to ConA predominantly through hydrogen bonds and water-mediated interactions. The sandwiched water molecules in the complex play a cementing role, facilitating favorable binding of porphyrin. Seven of the eight hydrogen bonds observed between methyl alpha-d-mannopyranoside and ConA are mimicked by the sulfonatophenyl group of porphyrin after incorporating two water molecules. Thus, the similarity in chemical interactions was manifested in terms of functional mimicry despite the obvious structural dissimilarity between the sugar and the porphyrin.


==About this Structure==
==About this Structure==
1JN2 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Canavalia_ensiformis Canavalia ensiformis] with CA, MN and SFP as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1JN2 OCA].  
1JN2 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Canavalia_ensiformis Canavalia ensiformis] with <scene name='pdbligand=CA:'>CA</scene>, <scene name='pdbligand=MN:'>MN</scene> and <scene name='pdbligand=SFP:'>SFP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JN2 OCA].  


==Reference==
==Reference==
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[[Category: Goel, M.]]
[[Category: Goel, M.]]
[[Category: Jain, D.]]
[[Category: Jain, D.]]
[[Category: Kaur, K.J.]]
[[Category: Kaur, K J.]]
[[Category: Kenoth, R.]]
[[Category: Kenoth, R.]]
[[Category: Maiya, B.G.]]
[[Category: Maiya, B G.]]
[[Category: Salunke, D.M.]]
[[Category: Salunke, D M.]]
[[Category: Swamy, M.J.]]
[[Category: Swamy, M J.]]
[[Category: CA]]
[[Category: CA]]
[[Category: MN]]
[[Category: MN]]
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[[Category: lectin]]
[[Category: lectin]]


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