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| - | [[Image:3cla.gif|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_3cla| PDB=3cla | SCENE= }} | | {{STRUCTURE_3cla| PDB=3cla | SCENE= }} |
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| - | '''REFINED CRYSTAL STRUCTURE OF TYPE III CHLORAMPHENICOL ACETYLTRANSFERASE AT 1.75 ANGSTROMS RESOLUTION'''
| + | ===REFINED CRYSTAL STRUCTURE OF TYPE III CHLORAMPHENICOL ACETYLTRANSFERASE AT 1.75 ANGSTROMS RESOLUTION=== |
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| - | ==Overview==
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| - | High level bacterial resistance to chloramphenicol is generally due to O-acetylation of the antibiotic in a reaction catalysed by chloramphenicol acetyltransferase (CAT, EC 2.3.1.28) in which acetyl-coenzyme A is the acyl donor. The crystal structure of the type III enzyme from Escherichia coli with chloramphenicol bound has been determined and refined at 1.75 A resolution, using a restrained parameter reciprocal space least squares procedure. The refined model, which includes chloramphenicol, 204 solvent molecules and two cobalt ions has a crystallographic R-factor of 18.3% for 27,300 reflections between 6 and 1.75 A resolution. The root-mean-square deviation in bond lengths from ideal values is 0.02 A. The cobalt ions play a crucial role in stabilizing the packing of the molecule in the crystal lattice. CAT is a trimer of identical subunits (monomer Mr 25,000) and the trimeric structure is stabilized by a number of hydrogen bonds, some of which result in the extension of a beta-sheet across the subunit interface. Chloramphenicol binds in a deep pocket located at the boundary between adjacent subunits of the trimer, such that the majority of residues forming the binding pocket belong to one subunit while the catalytically essential histidine belongs to the adjacent subunit. His195 is appropriately positioned to act as a general base catalyst in the reaction, and the required tautomeric stabilization is provided by an unusual interaction with a main-chain carbonyl oxygen.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_2187098}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 2187098 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_2187098}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Single protein]] | | [[Category: Single protein]] |
| | [[Category: Leslie, A G.W.]] | | [[Category: Leslie, A G.W.]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 21:52:38 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 14:07:19 2008'' |
Revision as of 11:07, 29 July 2008
Template:STRUCTURE 3cla
REFINED CRYSTAL STRUCTURE OF TYPE III CHLORAMPHENICOL ACETYLTRANSFERASE AT 1.75 ANGSTROMS RESOLUTION
Template:ABSTRACT PUBMED 2187098
About this Structure
3CLA is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Refined crystal structure of type III chloramphenicol acetyltransferase at 1.75 A resolution., Leslie AG, J Mol Biol. 1990 May 5;213(1):167-86. PMID:2187098
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