View source for 2a49

[[Image:2a49.gif|left|200px]]

 {{Structure
|PDB= 2a49 |SIZE=350|CAPTION= <scene name='initialview01'>2a49</scene>, resolution 1.43&Aring;
|SITE= 
|LIGAND= <scene name='pdbligand=TEM:N-(2-HYDROXY-4-OXO-BUTYL)-N-(3-OXO-TRANSPROPENYL)AMINE'>TEM</scene>, <scene name='pdbligand=MA4:CYCLOHEXYL-HEXYL-BETA-D-MALTOSIDE'>MA4</scene> and <scene name='pdbligand=EPE:4-(2-HYDROXYETHYL)-1-PIPERAZINE ETHANESULFONIC ACID'>EPE</scene>
|ACTIVITY= [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] 
|GENE= bla, shv1 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=573 Klebsiella pneumoniae])
}}

'''Crystal structure of clavulanic acid bound to E166A variant of SHV-1 beta-lactamase'''


==Overview==
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==
2A49 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Klebsiella_pneumoniae Klebsiella pneumoniae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2A49 OCA]. 

==Reference==
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:[http://www.ncbi.nlm.nih.gov/pubmed/16055923 16055923]
[[Category: Beta-lactamase]]
[[Category: Klebsiella pneumoniae]]
[[Category: Single protein]]
[[Category: Akker, F van den.]]
[[Category: Bonomo, R A.]]
[[Category: Carey, M P.]]
[[Category: Carey, P R.]]
[[Category: Helfand, M S.]]
[[Category: Padayatti, P S.]]
[[Category: Totir, M A.]]
[[Category: EPE]]
[[Category: MA4]]
[[Category: TEM]]
[[Category: beta-lactam hydrolase]]
[[Category: beta-lactamase]]
[[Category: covalent intermediate]]
[[Category: detergent binding]]
[[Category: inhibitor design]]
[[Category: penicillinase]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 15:45:12 2008''