6v5e: Difference between revisions
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==Crystal structure of CTX-M-14 P167S/D240G beta-lactamase== | ==Crystal structure of CTX-M-14 P167S/D240G beta-lactamase== | ||
<StructureSection load='6v5e' size='340' side='right'caption='[[6v5e]]' scene=''> | <StructureSection load='6v5e' size='340' side='right'caption='[[6v5e]], [[Resolution|resolution]] 2.30Å' scene=''> | ||
== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6V5E OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=6V5E FirstGlance]. <br> | <table><tr><td colspan='2'>[[6v5e]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_coli"_migula_1895 "bacillus coli" migula 1895]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6V5E OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=6V5E FirstGlance]. <br> | ||
</td></tr><tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=6v5e FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6v5e OCA], [http://pdbe.org/6v5e PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6v5e RCSB], [http://www.ebi.ac.uk/pdbsum/6v5e PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6v5e ProSAT]</span></td></tr> | </td></tr><tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=SEE:TRIHYDROXY(L-SERINATO-KAPPAO~3~)BORATE(1-)'>SEE</scene></td></tr> | ||
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">blaCTX-M-14, beta-lactamase CTX-M-14, bla, bla CTX-M-14, bla-CTX-M-14a, blaCTX-M, blaCTX-M-14a, blaCTX-M-14b, blaCTX-M-14c, blaCTX-M-27b, blatoho-3, blaUOE-2, CTX-M-14, AM465_01285, AM465_06510, AM465_23360, APT94_14605, BEN53_26220, BET08_34355, BJJ90_27545, BK334_27290, BOH76_00730, BON63_16015, BON66_01305, BON69_22545, BON71_04040, BON75_10525, BON76_14325, BON81_01055, BON83_15455, BON86_08515, BON91_02075, BON92_04750, BON94_23850, BON95_01680, BON96_03940, BXT93_06855, C5N07_28500, C5P43_21980, CDL37_21060, CR538_26855, CRT46_23505, DW236_20870, EIA08_25160, EIA21_26975, ELT23_05930, ETN48_p0088, FNJ69_13810, FQR64_24895, FTV90_03295, pCT_085, pHK01_011, RCS103_P0010, RCS30_P0082, RCS56_P0085, RCS60_P0031, RCS63_P0006, RCS65_P0008, RCS66_P0053, SAMEA4362930_00013, SAMEA4370290_00046 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 "Bacillus coli" Migula 1895])</td></tr> | |||
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Beta-lactamase Beta-lactamase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.2.6 3.5.2.6] </span></td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=6v5e FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6v5e OCA], [http://pdbe.org/6v5e PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6v5e RCSB], [http://www.ebi.ac.uk/pdbsum/6v5e PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6v5e ProSAT]</span></td></tr> | |||
</table> | </table> | ||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
CTX-M beta-lactamases are widespread in Gram-negative bacterial pathogens and provide resistance to the cephalosporin cefotaxime, but not to the related antibiotic, ceftazidime. Nevertheless, variants have emerged that confer resistance to ceftazidime. Two natural mutations, causing P167S and D240G substitutions in the CTX-M enzyme, result in 10-fold increased hydrolysis of ceftazidime. Although the combination of these mutations would be predicted to increase ceftazidime hydrolysis further, the P167S/D240G combination has not been observed in a naturally occurring CTX-M variant. Here, using recombinantly expressed enzymes, minimum inhibitory concentration measurements, steady-state enzyme kinetics, and X-ray crystallography, we show that the P167S/D240G double mutant enzyme exhibits decreased ceftazidime hydrolysis, lower thermostability, and decreased protein expression levels compared with each of the single mutants, indicating negative epistasis. X-ray structures of mutant enzymes with covalently trapped ceftazidime suggested that a change of an active site Omega-loop to an open conformation accommodates ceftazidime leading to enhanced catalysis. Ten microseconds of molecular dynamics simulations further correlated Omega-loop opening with catalytic activity. We observed that the wild type and P167S/D240G variant with acylated ceftazidime both favor a closed conformation not conducive for catalysis. In contrast, the single substitutions dramatically increased the probability of open conformations. We conclude that the antagonism is due to restricting the conformation of the Omega-loop. These results reveal the importance of conformational heterogeneity of active site loops in controlling catalytic activity and directing evolutionary trajectories. | |||
Antagonism between substitutions in beta-lactamase explains a path not taken in the evolution of bacterial drug resistance.,Brown CA, Hu L, Sun Z, Patel MP, Singh S, Porter JR, Sankaran B, Prasad BVV, Bowman GR, Palzkill T J Biol Chem. 2020 Apr 16. pii: RA119.012489. doi: 10.1074/jbc.RA119.012489. PMID:32299911<ref>PMID:32299911</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 6v5e" style="background-color:#fffaf0;"></div> | |||
== References == | |||
<references/> | |||
__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
[[Category: Bacillus coli migula 1895]] | |||
[[Category: Beta-lactamase]] | |||
[[Category: Large Structures]] | [[Category: Large Structures]] | ||
[[Category: Brown | [[Category: Brown, C A]] | ||
[[Category: Hu L]] | [[Category: Hu, L]] | ||
[[Category: Palzkill | [[Category: Palzkill, T G]] | ||
[[Category: Prasad | [[Category: Prasad, B V.V]] | ||
[[Category: Conformational change]] | |||
[[Category: Drug resistance]] | |||
[[Category: Enzyme catalysis]] | |||
[[Category: Enzyme kinetic]] | |||
[[Category: Hydrolase]] | |||
[[Category: Protein evolution]] | |||
[[Category: Protein stability]] | |||
[[Category: Protein-drug interaction]] | |||
Revision as of 10:14, 29 April 2020
Crystal structure of CTX-M-14 P167S/D240G beta-lactamaseCrystal structure of CTX-M-14 P167S/D240G beta-lactamase
Structural highlights
Publication Abstract from PubMedCTX-M beta-lactamases are widespread in Gram-negative bacterial pathogens and provide resistance to the cephalosporin cefotaxime, but not to the related antibiotic, ceftazidime. Nevertheless, variants have emerged that confer resistance to ceftazidime. Two natural mutations, causing P167S and D240G substitutions in the CTX-M enzyme, result in 10-fold increased hydrolysis of ceftazidime. Although the combination of these mutations would be predicted to increase ceftazidime hydrolysis further, the P167S/D240G combination has not been observed in a naturally occurring CTX-M variant. Here, using recombinantly expressed enzymes, minimum inhibitory concentration measurements, steady-state enzyme kinetics, and X-ray crystallography, we show that the P167S/D240G double mutant enzyme exhibits decreased ceftazidime hydrolysis, lower thermostability, and decreased protein expression levels compared with each of the single mutants, indicating negative epistasis. X-ray structures of mutant enzymes with covalently trapped ceftazidime suggested that a change of an active site Omega-loop to an open conformation accommodates ceftazidime leading to enhanced catalysis. Ten microseconds of molecular dynamics simulations further correlated Omega-loop opening with catalytic activity. We observed that the wild type and P167S/D240G variant with acylated ceftazidime both favor a closed conformation not conducive for catalysis. In contrast, the single substitutions dramatically increased the probability of open conformations. We conclude that the antagonism is due to restricting the conformation of the Omega-loop. These results reveal the importance of conformational heterogeneity of active site loops in controlling catalytic activity and directing evolutionary trajectories. Antagonism between substitutions in beta-lactamase explains a path not taken in the evolution of bacterial drug resistance.,Brown CA, Hu L, Sun Z, Patel MP, Singh S, Porter JR, Sankaran B, Prasad BVV, Bowman GR, Palzkill T J Biol Chem. 2020 Apr 16. pii: RA119.012489. doi: 10.1074/jbc.RA119.012489. PMID:32299911[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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