This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.

Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.


1ltt

From Proteopedia

(Difference between revisions)
Jump to: navigation, search
Current revision (08:27, 10 April 2024) (edit) (undo)
 
(16 intermediate revisions not shown.)
Line 1: Line 1:
-
[[Image:1ltt.jpg|left|200px]]<br /><applet load="1ltt" size="350" color="white" frame="true" align="right" spinBox="true"
 
-
caption="1ltt, resolution 2.3&Aring;" />
 
-
'''LACTOSE BINDING TO HEAT-LABILE ENTEROTOXIN REVEALED BY X-RAY CRYSTALLOGRAPHY'''<br />
 
-
==Overview==
+
==LACTOSE BINDING TO HEAT-LABILE ENTEROTOXIN REVEALED BY X-RAY CRYSTALLOGRAPHY==
-
Recognition of the oligosaccharide portion of ganglioside GM1 in membranes of target cells by the heat-labile enterotoxin from Escherichia coli is the crucial first step in its pathogenesis, as it is for the closely related cholera toxin. These toxins have five B subunits, which are essential for GM1 binding, and a single A subunit, which needs to be nicked by proteolysis and reduced, yielding an A1-'enzyme' and an A2-'linker' peptide. A1 is translocated across the membrane of intestinal epithelial cells, possibly after endocytosis, upon which it ADP-ribosylates the G protein Gs alpha. The mechanism of binding and translocation of these toxins has been extensively investigated, but how the protein is orientated on binding is still not clear. Knowing the precise arrangement of the ganglioside binding sites of the toxins will be useful for designing drugs against the diarrhoeal diseases caused by organisms secreting these toxins and in the development of oral vaccines against them. We present here the three-dimensional structure of the E. coli heat-labile enterotoxin complexed with lactose. This reveals the location of the binding site of the terminal galactose of GM1, which is consistent with toxin binding to the target cell with its A1 fragment pointing away from the membrane. A small helix is identified at the carboxy terminus of A2 which emerges through the central pore of the B subunits and probably comes into contact with the membrane upon binding, whereas the A1 subunit is flexible with respect to the B pentamer.
+
<StructureSection load='1ltt' size='340' side='right'caption='[[1ltt]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
-
 
+
== Structural highlights ==
-
==About this Structure==
+
<table><tr><td colspan='2'>[[1ltt]] is a 7 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. The September 2005 RCSB PDB [https://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/index.html Molecule of the Month] feature on ''Cholera Toxin'' by David S. Goodsell is [https://dx.doi.org/10.2210/rcsb_pdb/mom_2005_9 10.2210/rcsb_pdb/mom_2005_9]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LTT OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1LTT FirstGlance]. <br>
-
1LTT is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. The following page contains interesting information on the relation of 1LTT with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb69_1.html Cholera Toxin]]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LTT OCA].
+
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.3&#8491;</td></tr>
-
 
+
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BGC:BETA-D-GLUCOSE'>BGC</scene>, <scene name='pdbligand=GAL:BETA-D-GALACTOSE'>GAL</scene>, <scene name='pdbligand=PRD_900004:beta-lactose'>PRD_900004</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=1ltt FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ltt OCA], [https://pdbe.org/1ltt PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ltt RCSB], [https://www.ebi.ac.uk/pdbsum/1ltt PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ltt ProSAT]</span></td></tr>
-
Lactose binding to heat-labile enterotoxin revealed by X-ray crystallography., Sixma TK, Pronk SE, Kalk KH, van Zanten BA, Berghuis AM, Hol WG, Nature. 1992 Feb 6;355(6360):561-4. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=1741035 1741035]
+
</table>
 +
== Function ==
 +
[https://www.uniprot.org/uniprot/ELBP_ECOLX ELBP_ECOLX] The biological activity of the toxin is produced by the A chain, which activates intracellular adenyl cyclase.
 +
== 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/lt/1ltt_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=1ltt ConSurf].
 +
<div style="clear:both"></div>
 +
__TOC__
 +
</StructureSection>
[[Category: Cholera Toxin]]
[[Category: Cholera Toxin]]
[[Category: Escherichia coli]]
[[Category: Escherichia coli]]
-
[[Category: Protein complex]]
+
[[Category: Large Structures]]
-
[[Category: Hol, W G.J.]]
+
[[Category: RCSB PDB Molecule of the Month]]
-
[[Category: Sixma, T K.]]
+
[[Category: Hol WGJ]]
-
[[Category: toxin]]
+
[[Category: Sixma TK]]
-
 
+
-
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:48:25 2008''
+

Current revision

LACTOSE BINDING TO HEAT-LABILE ENTEROTOXIN REVEALED BY X-RAY CRYSTALLOGRAPHY

PDB ID 1ltt

Drag the structure with the mouse to rotate

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/1ltt"
Personal tools