1lxg: Difference between revisions

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-[[Image:1lxg.gif|left|200px]]<br /><applet load="1lxg" size="350" color="white" frame="true" align="right" spinBox="true"
-caption="1lxg" />
-'''Solution structure of alpha-cobratoxin complexed with a cognate peptide (structure ensemble)'''<br />
-==Overview==
+==Solution structure of alpha-cobratoxin complexed with a cognate peptide (structure ensemble)==
-The alpha18-mer peptide, spanning residues 181-198 of the Torpedo nicotinic acetylcholine receptor alpha1 subunit, contains key binding determinants for agonists and competitive antagonists. To investigate whether the alpha18-mer can bind other alpha-neurotoxins besides alpha-bungarotoxin, we designed a two-dimensional (1)H-(15)N heteronuclear single quantum correlation experiment to screen four related neurotoxins for their binding ability to the peptide. Of the four toxins tested (erabutoxin a, erabutoxin b, LSIII, and alpha-cobratoxin), only alpha-cobratoxin binds the alpha18-mer to form a 1:1 complex. The NMR solution structure of the alpha-cobratoxin.alpha18-mer complex was determined with a backbone root mean square deviation of 1.46 A. In the structure, alpha-cobratoxin contacts the alpha18-mer at the tips of loop I and II and through C-terminal cationic residues. The contact zone derived from the intermolecular nuclear Overhauser effects is in agreement with recent biochemical data. Furthermore, the structural models support the involvement of cation-pi interactions in stabilizing the complex. In addition, the binding screen results suggest that C-terminal cationic residues of alpha-bungarotoxin and alpha-cobratoxin contribute significantly to binding of the alpha18-mer. Finally, we present a structural model for nicotinic acetylcholine receptor-alpha-cobratoxin interaction by superimposing the alpha-cobratoxin.alpha18-mer complex onto the crystal structure of the acetylcholine-binding protein (Protein Data Bank code ).
+<StructureSection load='1lxg' size='340' side='right'caption='[[1lxg]]' scene=''>
+== Structural highlights ==
-==About this Structure==
+<table><tr><td colspan='2'>[[1lxg]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Naja_kaouthia Naja kaouthia] and [https://en.wikipedia.org/wiki/Tetronarce_californica Tetronarce californica]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LXG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1LXG FirstGlance]. <br>
-LXG is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Naja_kaouthia Naja kaouthia] and [http://en.wikipedia.org/wiki/Torpedo_californica Torpedo californica]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LXG OCA].
+</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</td></tr>
+<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HSL:HOMOSERINE+LACTONE'>HSL</scene></td></tr>
-==Reference==
+<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1lxg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1lxg OCA], [https://pdbe.org/1lxg PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1lxg RCSB], [https://www.ebi.ac.uk/pdbsum/1lxg PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1lxg ProSAT]</span></td></tr>
-NMR-based binding screen and structural analysis of the complex formed between alpha-cobratoxin and an 18-mer cognate peptide derived from the alpha 1 subunit of the nicotinic acetylcholine receptor from Torpedo californica., Zeng H, Hawrot E, J Biol Chem. 2002 Oct 4;277(40):37439-45. Epub 2002 Jul 19. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=12133834 12133834]
+</table>
+== Function ==
+[https://www.uniprot.org/uniprot/3L21_NAJKA 3L21_NAJKA] Monomer: binds with high affinity to muscular (alpha-1-beta-1-gamma-delta/CHRNA1-CHRNB1-CHRNG-CHRND) nAChR (tested on Torpedo californica, Kd=0.2-4.5 nM) and neuronal alpha-7/CHRNA7 nicotinic acetylcholine receptors (Kd=13-105 nM) (PubMed:18381281, PubMed:9305882, PubMed:22223648). Also inhibits GABA(A) channels (PubMed:26221036). Heteropentamer targets studied are composed of alpha-1-beta-3-gamma-2 (GABRA1-GABRB3-GABRG2) subunits (IC(50)=236 nM), alpha-1-beta-2-gamma-2 (GABRA1-GABRB2-GABRG2) subunits (IC(50)=469 nM), alpha-2-beta-2-gamma-2 (GABRA2-GABRB2-GABRG2) subunits (IC(50)=485 nM), alpha-5-beta-3-gamma-2 (GABRA5-GABRB3-GABRG2) subunits (IC(50)=635 nM), and alpha-2-beta-3-gamma-2 (GABRA2-GABRB3-GABRG2) subunits (IC(50)=1099 nM) (activated by 10 uM GABA) (PubMed:26221036).<ref>PMID:18381281</ref> <ref>PMID:22223648</ref> <ref>PMID:26221036</ref> <ref>PMID:30025921</ref>   Homodimer: binds with high affinity (but lower than the monomeric form) to muscular (IC(50)=9.7 nM) and with low affinity to neuronal alpha-7/CHRNA7 nAChRs (IC(50)=1370 nM) (PubMed:22223648). However, it acquires (compared to the monomeric form) the capacity to block alpha-3/beta-2 (CHRNA3/CHRNB2) nAChRs (PubMed:18381281).<ref>PMID:18381281</ref> <ref>PMID:22223648</ref>   Heterodimer with cytotoxin 3 (AC P01446): is slightly more active than the homodimer in inhibiting alpha-7/CHRNA7 nAChR and is considerably more active in blocking the alpha-3-beta-2/CHRNA3-CHRNB2 nAChR.<ref>PMID:22223648</ref>
+== Evolutionary Conservation ==
+[[Image:Consurf_key_small.gif|200px|right]]
+Check<jmol>
+  <jmolCheckbox>
+    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/lx/1lxg_consurf.spt"</scriptWhenChecked>
+    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
+    <text>to colour the structure by Evolutionary Conservation</text>
+  </jmolCheckbox>
+</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1lxg ConSurf].
+<div style="clear:both"></div>
+== References ==
+<references/>
+__TOC__
+</StructureSection>
+[[Category: Large Structures]]
 [[Category: Naja kaouthia]]
-[[Category: Protein complex]]
+[[Category: Tetronarce californica]]
-[[Category: Torpedo californica]]
+[[Category: Hawrot E]]
-[[Category: Hawrot, E.]]
+[[Category: Zeng H]]
-[[Category: Zeng, H.]]
-[[Category: alpha-cobratoxin]]
-[[Category: nicotinic acetylcholine receptor]]
-[[Category: protein-protein interaction]]
-[[Category: toxin]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:49:21 2008''