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1ltg

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(New page: 200px<br /><applet load="1ltg" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ltg, resolution 2.4&Aring;" /> '''THE ARG7LYS MUTANT OF...)
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[[Image:1ltg.gif|left|200px]]<br /><applet load="1ltg" size="450" color="white" frame="true" align="right" spinBox="true"
 
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caption="1ltg, resolution 2.4&Aring;" />
 
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'''THE ARG7LYS MUTANT OF HEAT-LABILE ENTEROTOXIN EXHIBITS GREAT FLEXIBILITY OF ACTIVE SITE LOOP 47-56 OF THE A SUBUNIT'''<br />
 
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==Overview==
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==THE ARG7LYS MUTANT OF HEAT-LABILE ENTEROTOXIN EXHIBITS GREAT FLEXIBILITY OF ACTIVE SITE LOOP 47-56 OF THE A SUBUNIT==
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The heat-labile enterotoxin from Escherichia coli (LT) is a member of the, cholera toxin family. These and other members of the larger class of AB5, bacterial toxins act through catalyzing the ADP-ribosylation of various, intracellular targets including Gs alpha. The A subunit is responsible for, this covalent modification, while the B pentamer is involved in receptor, recognition. We report here the crystal structure of an inactive, single-site mutant of LT in which arginine 7 of the A subunit has been, replaced by a lysine residue. The final model contains 103 residues for, each of the five B subunits, 175 residues for the A1 subunit, and 41, residues for the A2 subunit. In this Arg7Lys structure the active site, cleft within the A subunit is wider by approximately 1 A than is seen in, the wild-type LT. Furthermore, a loop near the active site consisting of, residues 47-56 is disordered in the Arg7Lys structure, even though the new, lysine residue at position 7 assumes a position which virtually coincides, with that of Arg7 in the wild-type structure. The displacement of residues, 47-56 as seen in the mutant structure is proposed to be necessary for, allowing NAD access to the active site of the wild-type LT. On the basis, of the differences observed between the wild-type and Arg7Lys structures, we propose a model for a coordinated sequence of conformational changes, required for full activation of LT upon reduction of disulfide bridge, 187-199 and cleavage of the peptide loop between the two cysteines in the, A subunit.(ABSTRACT TRUNCATED AT 250 WORDS)
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<StructureSection load='1ltg' size='340' side='right'caption='[[1ltg]], [[Resolution|resolution]] 2.40&Aring;' scene=''>
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== Structural highlights ==
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==About this Structure==
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<table><tr><td colspan='2'>[[1ltg]] 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=1LTG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1LTG FirstGlance]. <br>
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1LTG is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1LTG OCA].
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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]] 2.4&#8491;</td></tr>
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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=1ltg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ltg OCA], [https://pdbe.org/1ltg PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ltg RCSB], [https://www.ebi.ac.uk/pdbsum/1ltg PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ltg ProSAT]</span></td></tr>
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==Reference==
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</table>
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The Arg7Lys mutant of heat-labile enterotoxin exhibits great flexibility of active site loop 47-56 of the A subunit., van den Akker F, Merritt EA, Pizza M, Domenighini M, Rappuoli R, Hol WG, Biochemistry. 1995 Sep 5;34(35):10996-1004. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=7669757 7669757]
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== Function ==
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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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Check<jmol>
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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/1ltg_consurf.spt"</scriptWhenChecked>
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<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
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<text>to colour the structure by Evolutionary Conservation</text>
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</jmolCheckbox>
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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=1ltg ConSurf].
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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: Akker, F.Van.Den.]]
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[[Category: Hol WGJ]]
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[[Category: Hol, W.G.J.]]
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[[Category: Van Den Akker F]]
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[[Category: enterotoxin]]
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''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 20:52:02 2007''
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Current revision

THE ARG7LYS MUTANT OF HEAT-LABILE ENTEROTOXIN EXHIBITS GREAT FLEXIBILITY OF ACTIVE SITE LOOP 47-56 OF THE A SUBUNIT

PDB ID 1ltg

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