2a49: Difference between revisions
New page: left|200px<br /><applet load="2a49" size="450" color="white" frame="true" align="right" spinBox="true" caption="2a49, resolution 1.43Å" /> '''Crystal structure of... |
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[[Image:2a49.gif|left|200px]]<br /><applet load="2a49" size=" | [[Image:2a49.gif|left|200px]]<br /><applet load="2a49" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="2a49, resolution 1.43Å" /> | caption="2a49, resolution 1.43Å" /> | ||
'''Crystal structure of clavulanic acid bound to E166A variant of SHV-1 beta-lactamase'''<br /> | '''Crystal structure of clavulanic acid bound to E166A variant of SHV-1 beta-lactamase'''<br /> | ||
==Overview== | ==Overview== | ||
Antibiotic resistance mediated by constantly evolving beta-lactamases is a | Antibiotic resistance mediated by constantly evolving beta-lactamases is a serious threat to human health. The mechanism of inhibition of these enzymes by therapeutic beta-lactamase inhibitors is probed using a novel approach involving Raman microscopy and x-ray crystallography. We have presented here the high resolution crystal structures of the beta-lactamase inhibitors sulbactam and clavulanic acid bound to the deacylation-deficient E166A variant of SHV-1 beta-lactamase. Our previous Raman measurements have identified the trans-enamine species for both inhibitors and were used to guide the soaking time and concentration to achieve full occupancy of the active sites. The two inhibitor-bound x-ray structures revealed a linear trans-enamine intermediate covalently attached to the active site Ser-70 residue. This intermediate was thought to play a key role in the transient inhibition of class A beta-lactamases. Both the Raman and x-ray data indicated that the clavulanic acid intermediate is decarboxylated. When compared with our previously determined tazobactam-bound inhibitor structure, our new inhibitor-bound structures revealed an increased disorder in the tail region of the inhibitors as well as in the enamine skeleton. The x-ray crystallographic observations correlated with the broadening of the O-C=C-N (enamine) symmetric stretch Raman band near 1595 cm(-1). Band broadening in the sulbactam and clavulanic acid inter-mediates reflected a heterogeneous conformational population that results from variations of torsional angles in the O-(C=O)-C=C=NH-C skeleton. These observations led us to conclude that the conformational stability of the trans-enamine form is critical for their transient inhibitory efficacy. | ||
==About this Structure== | ==About this Structure== | ||
2A49 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Klebsiella_pneumoniae Klebsiella pneumoniae] with TEM, MA4 and EPE as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [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] Full crystallographic information is available from [http:// | 2A49 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Klebsiella_pneumoniae Klebsiella pneumoniae] with <scene name='pdbligand=TEM:'>TEM</scene>, <scene name='pdbligand=MA4:'>MA4</scene> and <scene name='pdbligand=EPE:'>EPE</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [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] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2A49 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Klebsiella pneumoniae]] | [[Category: Klebsiella pneumoniae]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Akker, F | [[Category: Akker, F van den.]] | ||
[[Category: Bonomo, R | [[Category: Bonomo, R A.]] | ||
[[Category: Carey, M | [[Category: Carey, M P.]] | ||
[[Category: Carey, P | [[Category: Carey, P R.]] | ||
[[Category: Helfand, M | [[Category: Helfand, M S.]] | ||
[[Category: Padayatti, P | [[Category: Padayatti, P S.]] | ||
[[Category: Totir, M | [[Category: Totir, M A.]] | ||
[[Category: EPE]] | [[Category: EPE]] | ||
[[Category: MA4]] | [[Category: MA4]] | ||
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[[Category: penicillinase]] | [[Category: penicillinase]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:23:27 2008'' | ||
Revision as of 17:23, 21 February 2008
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Crystal structure of clavulanic acid bound to E166A variant of SHV-1 beta-lactamase
OverviewOverview
Antibiotic resistance mediated by constantly evolving beta-lactamases is a serious threat to human health. The mechanism of inhibition of these enzymes by therapeutic beta-lactamase inhibitors is probed using a novel approach involving Raman microscopy and x-ray crystallography. We have presented here the high resolution crystal structures of the beta-lactamase inhibitors sulbactam and clavulanic acid bound to the deacylation-deficient E166A variant of SHV-1 beta-lactamase. Our previous Raman measurements have identified the trans-enamine species for both inhibitors and were used to guide the soaking time and concentration to achieve full occupancy of the active sites. The two inhibitor-bound x-ray structures revealed a linear trans-enamine intermediate covalently attached to the active site Ser-70 residue. This intermediate was thought to play a key role in the transient inhibition of class A beta-lactamases. Both the Raman and x-ray data indicated that the clavulanic acid intermediate is decarboxylated. When compared with our previously determined tazobactam-bound inhibitor structure, our new inhibitor-bound structures revealed an increased disorder in the tail region of the inhibitors as well as in the enamine skeleton. The x-ray crystallographic observations correlated with the broadening of the O-C=C-N (enamine) symmetric stretch Raman band near 1595 cm(-1). Band broadening in the sulbactam and clavulanic acid inter-mediates reflected a heterogeneous conformational population that results from variations of torsional angles in the O-(C=O)-C=C=NH-C skeleton. These observations led us to conclude that the conformational stability of the trans-enamine form is critical for their transient inhibitory efficacy.
About this StructureAbout this Structure
2A49 is a Single protein structure of sequence from Klebsiella pneumoniae with , and as ligands. Active as Beta-lactamase, with EC number 3.5.2.6 Full crystallographic information is available from OCA.
ReferenceReference
High resolution crystal structures of the trans-enamine intermediates formed by sulbactam and clavulanic acid and E166A SHV-1 {beta}-lactamase., Padayatti PS, Helfand MS, Totir MA, Carey MP, Carey PR, Bonomo RA, van den Akker F, J Biol Chem. 2005 Oct 14;280(41):34900-7. Epub 2005 Jul 29. PMID:16055923
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