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1cla

From Proteopedia

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[[Image:1cla.jpg|left|200px]]
 
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==EVIDENCE FOR TRANSITION-STATE STABILIZATION BY SERINE-148 IN THE CATALYTIC MECHANISM OF CHLORAMPHENICOL ACETYLTRANSFERASE==
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The line below this paragraph, containing "STRUCTURE_1cla", creates the "Structure Box" on the page.
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<StructureSection load='1cla' size='340' side='right'caption='[[1cla]], [[Resolution|resolution]] 2.34&Aring;' scene=''>
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You may change the PDB parameter (which sets the PDB file loaded into the applet)
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== Structural highlights ==
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or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
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<table><tr><td colspan='2'>[[1cla]] is a 1 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=1CLA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1CLA FirstGlance]. <br>
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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]] 2.34&#8491;</td></tr>
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<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CLM:CHLORAMPHENICOL'>CLM</scene>, <scene name='pdbligand=CO:COBALT+(II)+ION'>CO</scene></td></tr>
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{{STRUCTURE_1cla| PDB=1cla | SCENE= }}
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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=1cla FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1cla OCA], [https://pdbe.org/1cla PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1cla RCSB], [https://www.ebi.ac.uk/pdbsum/1cla PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1cla ProSAT]</span></td></tr>
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</table>
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== Function ==
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[https://www.uniprot.org/uniprot/CAT3_ECOLX CAT3_ECOLX] This enzyme is an effector of chloramphenicol resistance in bacteria.
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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/cl/1cla_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=1cla ConSurf].
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<div style="clear:both"></div>
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'''EVIDENCE FOR TRANSITION-STATE STABILIZATION BY SERINE-148 IN THE CATALYTIC MECHANISM OF CHLORAMPHENICOL ACETYLTRANSFERASE'''
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==See Also==
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*[[Chloramphenicol acetyltransferase 3D structures|Chloramphenicol acetyltransferase 3D structures]]
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__TOC__
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==Overview==
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</StructureSection>
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The function of conserved Ser-148 of chloramphenicol acetyltransferase (CAT) has been investigated by site-directed mutagenesis. Modeling studies (P. C. E. Moody and A. G. W. Leslie, unpublished results) suggested that the hydroxyl group of Ser-148 could be involved in transition-state stabilization via a hydrogen bond to the oxyanion of the putative tetrahedral intermediate. Replacement of serine by alanine results in a mutant enzyme (Ala-148 CAT) with kcat reduced 53-fold and only minor changes in Km values for chloramphenicol and acetyl-CoA. The Ser-148----Gly substitution gives rise to a mutant enzyme (Gly-148 CAT) with kcat reduced only 10-fold. A water molecule may partially replace the hydrogen-bonding potential of Ser-148 in Gly-148 CAT. The three-dimensional structure of Ala-148 CAT at 2.34-A resolution is isosteric with that of wild-type CAT with two exceptions: the absence of the Ser-148 hydroxyl group and the loss of one poorly ordered water molecule from the active site region. The results are consistent with a catalytic role for Ser-148 rather than a structural one and support the hypothesis that Ser-148 is involved in transition-state stabilization. Ser-148 has also been replaced with cysteine and asparagine; the Ser-148----Cys mutation results in a 705-fold decrease in kcat and the Ser-148----Asn substitution in a 214-fold reduction in kcat. Removing the hydrogen bond donor (Ser-148----Ala or Gly) is less deleterious than replacing Ser-148 with alternative possible hydrogen bond donors (Ser-148----Cys or Asn).
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==About this Structure==
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1CLA is a [[Single protein]] structure of sequence 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=1CLA OCA].
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==Reference==
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Evidence for transition-state stabilization by serine-148 in the catalytic mechanism of chloramphenicol acetyltransferase., Lewendon A, Murray IA, Shaw WV, Gibbs MR, Leslie AG, Biochemistry. 1990 Feb 27;29(8):2075-80. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/2109633 2109633]
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[[Category: Chloramphenicol O-acetyltransferase]]
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[[Category: Escherichia coli]]
[[Category: Escherichia coli]]
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[[Category: Single protein]]
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[[Category: Large Structures]]
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[[Category: Gibbs, M R.]]
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[[Category: Gibbs MR]]
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[[Category: Leslie, A G.W.]]
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[[Category: Leslie AGW]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 12:51:30 2008''
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Current revision

EVIDENCE FOR TRANSITION-STATE STABILIZATION BY SERINE-148 IN THE CATALYTIC MECHANISM OF CHLORAMPHENICOL ACETYLTRANSFERASE

PDB ID 1cla

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