1h9p
From Proteopedia
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| - | [[Image:1h9p.gif|left|200px]]<br /> | + | [[Image:1h9p.gif|left|200px]]<br /><applet load="1h9p" size="450" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1h9p" size="450" color="white" frame="true" align="right" spinBox="true" | + | |
caption="1h9p, resolution 2.00Å" /> | caption="1h9p, resolution 2.00Å" /> | ||
'''CRYSTAL STRUCTURE OF DIOCLEA GUIANENSIS SEED LECTIN'''<br /> | '''CRYSTAL STRUCTURE OF DIOCLEA GUIANENSIS SEED LECTIN'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1H9P 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 CD and MN as [http://en.wikipedia.org/wiki/ligands ligands]. | + | 1H9P 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 CD and MN as [http://en.wikipedia.org/wiki/ligands ligands]. Known structural/functional Sites: <scene name='pdbsite=AC1:Cd Binding Site For Residue A238'>AC1</scene>, <scene name='pdbsite=AC2:Cd Binding Site For Residue A239'>AC2</scene>, <scene name='pdbsite=AC3:Cd Binding Site For Residue A501'>AC3</scene>, <scene name='pdbsite=AC4:Mn Binding Site For Residue A502'>AC4</scene>, <scene name='pdbsite=AC5:Mn Binding Site For Residue A503'>AC5</scene> and <scene name='pdbsite=AC6:Mn Binding Site For Residue A504'>AC6</scene>. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1H9P OCA]. |
==Reference== | ==Reference== | ||
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[[Category: legume lectin oligomerisation]] | [[Category: legume lectin oligomerisation]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Dec 18 16:10:25 2007'' |
Revision as of 14:00, 18 December 2007
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CRYSTAL STRUCTURE OF 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
1H9P is a Single protein structure of sequence from Dioclea guianensis with CD and MN as ligands. Known structural/functional Sites: , , , , and . 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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