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1lts

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[[Image:1lts.jpg|left|200px]]
 
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{{Structure
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==REFINED STRUCTURE OF E. COLI HEAT LABILE ENTEROTOXIN, A CLOSE RELATIVE OF CHOLERA TOXIN==
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|PDB= 1lts |SIZE=350|CAPTION= <scene name='initialview01'>1lts</scene>, resolution 1.95&Aring;
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<StructureSection load='1lts' size='340' side='right'caption='[[1lts]], [[Resolution|resolution]] 1.95&Aring;' scene=''>
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|SITE=
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== Structural highlights ==
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|LIGAND=
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<table><tr><td colspan='2'>[[1lts]] is a 7 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LTS OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1LTS FirstGlance]. <br>
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|ACTIVITY=
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</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.95&#8491;</td></tr>
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|GENE=
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<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1lts FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1lts OCA], [https://pdbe.org/1lts PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1lts RCSB], [https://www.ebi.ac.uk/pdbsum/1lts PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1lts ProSAT]</span></td></tr>
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}}
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</table>
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== Function ==
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'''REFINED STRUCTURE OF E. COLI HEAT LABILE ENTEROTOXIN, A CLOSE RELATIVE OF CHOLERA TOXIN'''
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[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.
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== Evolutionary Conservation ==
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[[Image:Consurf_key_small.gif|200px|right]]
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==Overview==
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Check<jmol>
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Heat-labile enterotoxin (LT) from Escherichia coli is a bacterial protein toxin with an AB5 multimer structure, in which the B pentamer has a membrane binding function and the A subunit is needed for enzymatic activity. The LT crystal structure has been solved using a combination of multiple isomorphous replacement, fivefold averaging and molecular dynamics refinement. Phase combination using all these sources of phase information was of crucial importance for the chain tracing. The structure has now been refined to 1.95 A resolution, resulting in a model containing 6035 protein atoms and 293 solvent molecules with a crystallographic R-factor of 18.2% and good stereochemistry. The B subunits are arranged as a highly stable pentamer with a donut shape. Each subunit takes part in approximately 30 inter-subunit hydrogen bonds and six salt bridges with its two neighbors, whilst burying a large surface area. The A subunit has higher temperature factors and less well-defined secondary structure than the B subunits. It interacts with the B pentamer mainly via the C-terminal A2 fragment, which runs through the highly charged central pore of the B subunits. The pore contains at least 66 water molecules, which fill the space left by the A2 fragment. A detailed analysis of the contacts between A and B subunits showed that most specific contacts occur at the entrance of the central pore of the B pentamer, while the contacts within the pore are mainly hydrophobic and water mediated, with the exception of two salt bridges. Only a few contacts exist between the A1 fragment and the B pentamer, showing that the A2 fragment functions as a "linker" of the A and B parts of the protein. Interacting with the A subunit by the B subunits does not cause large deviations from a common B subunit structure, and the 5-fold symmetry is well maintained. A potential NAD(+)-binding site is located in an elongated crevice at the interface of two small sheets in the A1 fragment. At the back of this crevice the functionally important Arg7 makes a hydrogen bond connecting two strands, which seems to be conserved across the ADP-ribosylating toxin family. The putative catalytic residue (A1:Glu112) is located nearby, close to a very hydrophobic region, which packs two loops together. This hydrophobic region may be important for catalysis and membrane translocation.
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<jmolCheckbox>
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<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/lt/1lts_consurf.spt"</scriptWhenChecked>
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==About this Structure==
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<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
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1LTS is a [[Protein complex]] structure of sequences from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LTS OCA].
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<text>to colour the structure by Evolutionary Conservation</text>
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</jmolCheckbox>
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==Reference==
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</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=1lts ConSurf].
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Refined structure of Escherichia coli heat-labile enterotoxin, a close relative of cholera toxin., Sixma TK, Kalk KH, van Zanten BA, Dauter Z, Kingma J, Witholt B, Hol WG, J Mol Biol. 1993 Apr 5;230(3):890-918. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/8478941 8478941]
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<div style="clear:both"></div>
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__TOC__
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</StructureSection>
[[Category: Escherichia coli]]
[[Category: Escherichia coli]]
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[[Category: Protein complex]]
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[[Category: Large Structures]]
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[[Category: Hol, W G.J.]]
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[[Category: Hol WGJ]]
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[[Category: Sixma, T K.]]
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[[Category: Sixma TK]]
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[[Category: toxin]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 12:35:10 2008''
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Current revision

REFINED STRUCTURE OF E. COLI HEAT LABILE ENTEROTOXIN, A CLOSE RELATIVE OF CHOLERA TOXIN

PDB ID 1lts

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