4cla: Difference between revisions

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New page: left|200px<br /><applet load="4cla" size="450" color="white" frame="true" align="right" spinBox="true" caption="4cla, resolution 2.0Å" /> '''ALTERNATIVE BINDING M...
 
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[[Image:4cla.gif|left|200px]]<br /><applet load="4cla" size="450" color="white" frame="true" align="right" spinBox="true"
caption="4cla, resolution 2.0&Aring;" />
'''ALTERNATIVE BINDING MODES FOR CHLORAMPHENICOL AND 1-SUBSTITUTED CHLORAMPHENICOL ANALOGUES REVEALED BY SITE-DIRECTED MUTAGENESIS AND X-RAY CRYSTALLOGRAPHY OF CHLORAMPHENICOL ACETYLTRANSFERASE'''<br />


==Overview==
==ALTERNATIVE BINDING MODES FOR CHLORAMPHENICOL AND 1-SUBSTITUTED CHLORAMPHENICOL ANALOGUES REVEALED BY SITE-DIRECTED MUTAGENESIS AND X-RAY CRYSTALLOGRAPHY OF CHLORAMPHENICOL ACETYLTRANSFERASE==
Leucine-160 of chloramphenicol acetyltransferase (CAT) has been replaced, by site-directed mutagenesis to investigate enzyme-ligand interactions at, the 1-hydroxyl substituent of the substrate chloramphenicol. The, consequences of the substitution of Leu-160 by glutamine and by, phenylalanine were deduced from the steady-state kinetic parameters for, acetyl transfer from acetyl-CoA to the 3-hydroxyl of chloramphenicol and, its analogues 1-deoxychloramphenicol and 1-acetylchloramphenicol. The, acetyl group of the latter, which is a substrate both in vivo and in, vitro, could potentially bind in a similar position to the 1-hydroxyl of, chloramphenicol, in close proximity to the side chain of Leu-160. In the, case of Gln-160 CAT, large increases in Km for the three acetyl acceptors, were accompanied by small decreases in kcat and in apparent affinity for, acetyl-CoA. Such results are consistent with the introduction of the, relatively hydrophilic amide in place of the delta-methyl groups of, Leu-160. The kinetic properties of Phe-160 CAT were unexpected in that Km, for each of the three acetyl acceptors was unchanged or reduced, compared, to the equivalent parameters for the wild-type enzyme, whereas kcat fell, significantly (44-83-fold) in each case. The ratios of specificity, constants (kcat/Km) for the acetylation of chloramphenicol compared with, the alternative acyl acceptors were similar for wild-type and mutant, enzymes. As the residue substitutions for Leu-160 do not result in, enhanced discrimination against the binding and acetylation of, 1-acetylchloramphenicol, it appears unlikely that the 1-acetyl group binds, to the CAT active site in the same position as that occupied by the, 1-hydroxyl of chloramphenicol.(ABSTRACT TRUNCATED AT 250 WORDS)
<StructureSection load='4cla' size='340' side='right'caption='[[4cla]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4cla]] 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=4CLA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4CLA FirstGlance]. <br>
</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&#8491;</td></tr>
<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>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4cla FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4cla OCA], [https://pdbe.org/4cla PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4cla RCSB], [https://www.ebi.ac.uk/pdbsum/4cla PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4cla ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CAT3_ECOLX CAT3_ECOLX] This enzyme is an effector of chloramphenicol resistance in bacteria.
== 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/cl/4cla_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=4cla ConSurf].
<div style="clear:both"></div>


==About this Structure==
==See Also==
4CLA is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with CO and CLM as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Chloramphenicol_O-acetyltransferase Chloramphenicol O-acetyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.1.28 2.3.1.28] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=4CLA OCA].
*[[Chloramphenicol acetyltransferase 3D structures|Chloramphenicol acetyltransferase 3D structures]]
 
__TOC__
==Reference==
</StructureSection>
Alternative binding modes for chloramphenicol and 1-substituted chloramphenicol analogues revealed by site-directed mutagenesis and X-ray crystallography of chloramphenicol acetyltransferase., Murray IA, Lewendon A, Williams JA, Cullis PM, Shaw WV, Leslie AG, Biochemistry. 1991 Apr 16;30(15):3763-70. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=2015231 2015231]
[[Category: Chloramphenicol O-acetyltransferase]]
[[Category: Escherichia coli]]
[[Category: Escherichia coli]]
[[Category: Single protein]]
[[Category: Large Structures]]
[[Category: Leslie, A.G.W.]]
[[Category: Leslie AGW]]
[[Category: CLM]]
[[Category: CO]]
[[Category: transferase (acyltransferase)]]
 
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 19:29:04 2007''

Latest revision as of 13:41, 1 March 2024

ALTERNATIVE BINDING MODES FOR CHLORAMPHENICOL AND 1-SUBSTITUTED CHLORAMPHENICOL ANALOGUES REVEALED BY SITE-DIRECTED MUTAGENESIS AND X-RAY CRYSTALLOGRAPHY OF CHLORAMPHENICOL ACETYLTRANSFERASEALTERNATIVE BINDING MODES FOR CHLORAMPHENICOL AND 1-SUBSTITUTED CHLORAMPHENICOL ANALOGUES REVEALED BY SITE-DIRECTED MUTAGENESIS AND X-RAY CRYSTALLOGRAPHY OF CHLORAMPHENICOL ACETYLTRANSFERASE

Structural highlights

4cla is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2Å
Ligands:,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

CAT3_ECOLX This enzyme is an effector of chloramphenicol resistance in bacteria.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

See Also

4cla, resolution 2.00Å

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