1h9w
From Proteopedia
(New page: 200px<br /><applet load="1h9w" size="450" color="white" frame="true" align="right" spinBox="true" caption="1h9w, resolution 2.00Å" /> '''NATIVE DIOCLEA GUIAN...) |
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| - | [[Image:1h9w.gif|left|200px]]<br /><applet load="1h9w" size=" | + | [[Image:1h9w.gif|left|200px]]<br /><applet load="1h9w" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1h9w, resolution 2.00Å" /> | caption="1h9w, resolution 2.00Å" /> | ||
'''NATIVE DIOCLEA GUIANENSIS SEED LECTIN'''<br /> | '''NATIVE DIOCLEA GUIANENSIS SEED LECTIN'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Diocleinae legume lectins are a group of oligomeric proteins whose | + | Diocleinae legume lectins are a group of oligomeric proteins whose subunits display a high degree of primary structure and tertiary fold conservation but exhibit considerable diversity in their oligomerisation modes. To elucidate the structural determinants underlaying Diocleinae lectin oligomerisation, we have determined the crystal structures of native and cadmium-substituted Dioclea guianensis (Dguia) seed lectin. These structures have been solved by molecular replacement using concanavalin (ConA) coordinates as the starting model, and refined against data to 2.0 A resolution. In the native (Mn/Ca-Dguia) crystal form (P4(3)2(1)2), the asymmetric unit contains two monomers arranged into a canonical legume lectin dimer, and the tetramer is formed with a symmetry-related dimer. In the Cd/Cd-substituted form (I4(1)22), the asymmetric unit is occupied by a monomer. In both crystal forms, the tetrameric association is achieved by the corresponding symmetry operators. Like other legume lectins, native D. guianensis lectin contains manganese and calcium ions bound in the vicinity of the saccharide-combining site. The architecture of these metal-binding sites (S1 and S2) changed only slightly in the cadmium/cadmium-substituted form. A highly ordered calcium (native lectin) or cadmium (Cd/Cd-substituted lectin) ion is coordinated at the interface between dimers that are not tetrameric partners in a similar manner as the previously identified Cd(2+) in site S3 of a Cd/Ca-ConA. An additional Mn(2+) coordination site (called S5), whose presence has not been reported in crystal structures of any other homologous lectin, is present in both, the Mn/Ca and the Cd/Cd-substituted D. guianensis lectin forms. On the other hand, comparison of the primary and quaternary crystal structures of seed lectins from D. guianensis and Dioclea grandiflora (1DGL) indicates that the loop comprising residues 117-123 is ordered to make interdimer contacts in the D. grandiflora lectin structure, while this loop is disordered in the D. guianensis lectin structure. A single amino acid difference at position 131 (histidine in D. grandiflora and asparagine in D. guianensis) drastically reduces interdimer contacts, accounting for the disordered loop. Further, this amino acid change yields a conformation that may explain why a pH-dependent dimer-tetramer equilibrium exists for the D. guianensis lectin but not for the D. grandiflora lectin. |
==About this Structure== | ==About this Structure== | ||
| - | 1H9W is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Dioclea_guianensis Dioclea guianensis] with MN and CA as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1H9W is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Dioclea_guianensis Dioclea guianensis] with <scene name='pdbligand=MN:'>MN</scene> and <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1H9W OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Dioclea guianensis]] | [[Category: Dioclea guianensis]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Calvete, J | + | [[Category: Calvete, J J.]] |
| - | [[Category: Cavada, B | + | [[Category: Cavada, B S.]] |
| - | [[Category: Grangeiro, T | + | [[Category: Grangeiro, T B.]] |
| - | [[Category: Ramos, M | + | [[Category: Ramos, M V.]] |
[[Category: Romero, A.]] | [[Category: Romero, A.]] | ||
| - | [[Category: Sampaio, A | + | [[Category: Sampaio, A H.]] |
| - | [[Category: Sol, F | + | [[Category: Sol, F G.D.]] |
| - | [[Category: Wah, D | + | [[Category: Wah, D A.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: MN]] | [[Category: MN]] | ||
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[[Category: legume lectin oligomerisation]] | [[Category: legume lectin oligomerisation]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:59:00 2008'' |
Revision as of 10:59, 21 February 2008
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NATIVE DIOCLEA GUIANENSIS SEED LECTIN
Overview
Diocleinae legume lectins are a group of oligomeric proteins whose subunits display a high degree of primary structure and tertiary fold conservation but exhibit considerable diversity in their oligomerisation modes. To elucidate the structural determinants underlaying Diocleinae lectin oligomerisation, we have determined the crystal structures of native and cadmium-substituted Dioclea guianensis (Dguia) seed lectin. These structures have been solved by molecular replacement using concanavalin (ConA) coordinates as the starting model, and refined against data to 2.0 A resolution. In the native (Mn/Ca-Dguia) crystal form (P4(3)2(1)2), the asymmetric unit contains two monomers arranged into a canonical legume lectin dimer, and the tetramer is formed with a symmetry-related dimer. In the Cd/Cd-substituted form (I4(1)22), the asymmetric unit is occupied by a monomer. In both crystal forms, the tetrameric association is achieved by the corresponding symmetry operators. Like other legume lectins, native D. guianensis lectin contains manganese and calcium ions bound in the vicinity of the saccharide-combining site. The architecture of these metal-binding sites (S1 and S2) changed only slightly in the cadmium/cadmium-substituted form. A highly ordered calcium (native lectin) or cadmium (Cd/Cd-substituted lectin) ion is coordinated at the interface between dimers that are not tetrameric partners in a similar manner as the previously identified Cd(2+) in site S3 of a Cd/Ca-ConA. An additional Mn(2+) coordination site (called S5), whose presence has not been reported in crystal structures of any other homologous lectin, is present in both, the Mn/Ca and the Cd/Cd-substituted D. guianensis lectin forms. On the other hand, comparison of the primary and quaternary crystal structures of seed lectins from D. guianensis and Dioclea grandiflora (1DGL) indicates that the loop comprising residues 117-123 is ordered to make interdimer contacts in the D. grandiflora lectin structure, while this loop is disordered in the D. guianensis lectin structure. A single amino acid difference at position 131 (histidine in D. grandiflora and asparagine in D. guianensis) drastically reduces interdimer contacts, accounting for the disordered loop. Further, this amino acid change yields a conformation that may explain why a pH-dependent dimer-tetramer equilibrium exists for the D. guianensis lectin but not for the D. grandiflora lectin.
About this Structure
1H9W is a Single protein structure of sequence from Dioclea guianensis with and as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structure of native and Cd/Cd-substituted Dioclea guianensis seed lectin. A novel manganese-binding site and structural basis of dimer-tetramer association., Wah DA, Romero A, Gallego del Sol F, Cavada BS, Ramos MV, Grangeiro TB, Sampaio AH, Calvete JJ, J Mol Biol. 2001 Jul 20;310(4):885-94. PMID:11453695
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