4cla
From Proteopedia
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| - | [[Image:4cla.gif|left|200px]] | + | [[Image:4cla.gif|left|200px]] |
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| - | '''ALTERNATIVE BINDING MODES FOR CHLORAMPHENICOL AND 1-SUBSTITUTED CHLORAMPHENICOL ANALOGUES REVEALED BY SITE-DIRECTED MUTAGENESIS AND X-RAY CRYSTALLOGRAPHY OF CHLORAMPHENICOL ACETYLTRANSFERASE''' | + | {{Structure |
| + | |PDB= 4cla |SIZE=350|CAPTION= <scene name='initialview01'>4cla</scene>, resolution 2.0Å | ||
| + | |SITE= | ||
| + | |LIGAND= <scene name='pdbligand=CO:COBALT+(II)+ION'>CO</scene> and <scene name='pdbligand=CLM:CHLORAMPHENICOL'>CLM</scene> | ||
| + | |ACTIVITY= [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] | ||
| + | |GENE= | ||
| + | }} | ||
| + | |||
| + | '''ALTERNATIVE BINDING MODES FOR CHLORAMPHENICOL AND 1-SUBSTITUTED CHLORAMPHENICOL ANALOGUES REVEALED BY SITE-DIRECTED MUTAGENESIS AND X-RAY CRYSTALLOGRAPHY OF CHLORAMPHENICOL ACETYLTRANSFERASE''' | ||
| + | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 4CLA is a [ | + | 4CLA 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=4CLA OCA]. |
==Reference== | ==Reference== | ||
| - | 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:// | + | 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://www.ncbi.nlm.nih.gov/pubmed/2015231 2015231] |
[[Category: Chloramphenicol O-acetyltransferase]] | [[Category: Chloramphenicol O-acetyltransferase]] | ||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
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[[Category: transferase (acyltransferase)]] | [[Category: transferase (acyltransferase)]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 19:09:12 2008'' |
Revision as of 17:09, 20 March 2008
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| , resolution 2.0Å | |||||||
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| Ligands: | and | ||||||
| Activity: | Chloramphenicol O-acetyltransferase, with EC number 2.3.1.28 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
ALTERNATIVE BINDING MODES FOR CHLORAMPHENICOL AND 1-SUBSTITUTED CHLORAMPHENICOL ANALOGUES REVEALED BY SITE-DIRECTED MUTAGENESIS AND X-RAY CRYSTALLOGRAPHY OF CHLORAMPHENICOL ACETYLTRANSFERASE
Overview
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)
About this Structure
4CLA is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
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:2015231
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