4f6h: Difference between revisions
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==Mutagenesis of zinc ligand residue Cys221 reveals plasticity in the IMP-1 metallo-b-lactamase active site== | |||
<StructureSection load='4f6h' size='340' side='right' caption='[[4f6h]], [[Resolution|resolution]] 1.74Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[4f6h]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Pseudomonas_aeruginosa Pseudomonas aeruginosa]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4F6H OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4F6H FirstGlance]. <br> | |||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr> | |||
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4f6z|4f6z]]</td></tr> | |||
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">blaIMP-1, bla IMP, bla-imp, blaESP, imp ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=287 Pseudomonas aeruginosa])</td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4f6h FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4f6h OCA], [http://www.rcsb.org/pdb/explore.do?structureId=4f6h RCSB], [http://www.ebi.ac.uk/pdbsum/4f6h PDBsum]</span></td></tr> | |||
</table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Metallo-beta-lactamases catalyze the hydrolysis of a broad range of beta-lactam antibiotics and are a concern for the spread of drug resistance. To analyze the determinants of enzyme structure and function, the sequence requirements for the subclass B1 IMP-1 beta-lactamase zinc binding residue Cys221 were tested by saturation mutagenesis and evaluated for protein expression, as well as hydrolysis of beta-lactam substrates. The results indicated that most substitutions at position 221 destabilized the enzyme. Only the enzymes containing C221D and C221G substitutions were expressed well in Escherichia coli and exhibited catalytic activity toward beta-lactam antibiotics. Despite the lack of a metal-chelating group at position 221, the C221G enzyme exhibited high levels of catalytic activity in the presence of exogenous zinc. Molecular modeling suggests the glycine substitution is unique among substitutions in that the complete removal of the cysteine side chain allows space for a water molecule to replace the thiol and coordinate zinc at the Zn2 zinc binding site to restore function. Multiple methods were used to estimate the C221G Zn2 binding constant to be 17 to 43 muM. Studies of enzyme function in vivo in E. coli grown on minimal medium showed that both IMP-1 and the C221G mutant exhibited compromised activity when zinc availability was low. Finally, substitutions at residue 121, which is the IMP-1 equivalent of the subclass B3 zinc-chelating position, failed to rescue C221G function, suggesting the coordination schemes of subclasses B1 and B3 are not interchangeable. | |||
Mutagenesis of zinc ligand residue Cys221 reveals plasticity in the IMP-1 metallo-beta-lactamase active site.,Horton LB, Shanker S, Mikulski R, Brown NG, Phillips KJ, Lykissa E, Venkataram Prasad BV, Palzkill T Antimicrob Agents Chemother. 2012 Nov;56(11):5667-77. doi: 10.1128/AAC.01276-12. , Epub 2012 Aug 20. PMID:22908171<ref>PMID:22908171</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | |||
*[[Beta-lactamase|Beta-lactamase]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Pseudomonas aeruginosa]] | [[Category: Pseudomonas aeruginosa]] | ||
[[Category: Brown, N G | [[Category: Brown, N G]] | ||
[[Category: Horton, L B | [[Category: Horton, L B]] | ||
[[Category: Lykissa, E | [[Category: Lykissa, E]] | ||
[[Category: Mikulski, R | [[Category: Mikulski, R]] | ||
[[Category: Palzkill, T G | [[Category: Palzkill, T G]] | ||
[[Category: Phillips, K | [[Category: Phillips, K]] | ||
[[Category: Prasad, B V.V | [[Category: Prasad, B V.V]] | ||
[[Category: Shanker, S | [[Category: Shanker, S]] | ||
[[Category: B-lactamase]] | [[Category: B-lactamase]] | ||
[[Category: Hydrolase]] | [[Category: Hydrolase]] | ||
[[Category: Metallo-b-lactamase]] | [[Category: Metallo-b-lactamase]] | ||
Revision as of 14:05, 20 January 2015
Mutagenesis of zinc ligand residue Cys221 reveals plasticity in the IMP-1 metallo-b-lactamase active siteMutagenesis of zinc ligand residue Cys221 reveals plasticity in the IMP-1 metallo-b-lactamase active site
Structural highlights
Publication Abstract from PubMedMetallo-beta-lactamases catalyze the hydrolysis of a broad range of beta-lactam antibiotics and are a concern for the spread of drug resistance. To analyze the determinants of enzyme structure and function, the sequence requirements for the subclass B1 IMP-1 beta-lactamase zinc binding residue Cys221 were tested by saturation mutagenesis and evaluated for protein expression, as well as hydrolysis of beta-lactam substrates. The results indicated that most substitutions at position 221 destabilized the enzyme. Only the enzymes containing C221D and C221G substitutions were expressed well in Escherichia coli and exhibited catalytic activity toward beta-lactam antibiotics. Despite the lack of a metal-chelating group at position 221, the C221G enzyme exhibited high levels of catalytic activity in the presence of exogenous zinc. Molecular modeling suggests the glycine substitution is unique among substitutions in that the complete removal of the cysteine side chain allows space for a water molecule to replace the thiol and coordinate zinc at the Zn2 zinc binding site to restore function. Multiple methods were used to estimate the C221G Zn2 binding constant to be 17 to 43 muM. Studies of enzyme function in vivo in E. coli grown on minimal medium showed that both IMP-1 and the C221G mutant exhibited compromised activity when zinc availability was low. Finally, substitutions at residue 121, which is the IMP-1 equivalent of the subclass B3 zinc-chelating position, failed to rescue C221G function, suggesting the coordination schemes of subclasses B1 and B3 are not interchangeable. Mutagenesis of zinc ligand residue Cys221 reveals plasticity in the IMP-1 metallo-beta-lactamase active site.,Horton LB, Shanker S, Mikulski R, Brown NG, Phillips KJ, Lykissa E, Venkataram Prasad BV, Palzkill T Antimicrob Agents Chemother. 2012 Nov;56(11):5667-77. doi: 10.1128/AAC.01276-12. , Epub 2012 Aug 20. PMID:22908171[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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