1n9b: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Image:1n9b.jpg|left|200px]] | [[Image:1n9b.jpg|left|200px]] | ||
'''Ultrahigh resolution structure of a class A beta-lactamase: On the mechanism and specificity of the extended-spectrum SHV-2 enzyme''' | {{Structure | ||
|PDB= 1n9b |SIZE=350|CAPTION= <scene name='initialview01'>1n9b</scene>, resolution 0.90Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=MA4:CYCLOHEXYL-HEXYL-BETA-D-MALTOSIDE'>MA4</scene>, <scene name='pdbligand=EPE:4-(2-HYDROXYETHYL)-1-PIPERAZINE+ETHANESULFONIC+ACID'>EPE</scene> and <scene name='pdbligand=MPD:(4S)-2-METHYL-2,4-PENTANEDIOL'>MPD</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 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=573 Klebsiella pneumoniae]) | |||
}} | |||
'''Ultrahigh resolution structure of a class A beta-lactamase: On the mechanism and specificity of the extended-spectrum SHV-2 enzyme''' | |||
==Overview== | ==Overview== | ||
| Line 7: | Line 16: | ||
==About this Structure== | ==About this Structure== | ||
1N9B is a [ | 1N9B 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=1N9B OCA]. | ||
==Reference== | ==Reference== | ||
Ultrahigh resolution structure of a class A beta-lactamase: on the mechanism and specificity of the extended-spectrum SHV-2 enzyme., Nukaga M, Mayama K, Hujer AM, Bonomo RA, Knox JR, J Mol Biol. 2003 Apr 18;328(1):289-301. PMID:[http:// | Ultrahigh resolution structure of a class A beta-lactamase: on the mechanism and specificity of the extended-spectrum SHV-2 enzyme., Nukaga M, Mayama K, Hujer AM, Bonomo RA, Knox JR, J Mol Biol. 2003 Apr 18;328(1):289-301. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/12684014 12684014] | ||
[[Category: Beta-lactamase]] | [[Category: Beta-lactamase]] | ||
[[Category: Klebsiella pneumoniae]] | [[Category: Klebsiella pneumoniae]] | ||
| Line 28: | Line 37: | ||
[[Category: radiation damage]] | [[Category: radiation damage]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 12:53:49 2008'' | ||
Revision as of 13:53, 20 March 2008
| |||||||
| , resolution 0.90Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , and | ||||||
| Gene: | BLA (Klebsiella pneumoniae) | ||||||
| Activity: | Beta-lactamase, with EC number 3.5.2.6 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Ultrahigh resolution structure of a class A beta-lactamase: On the mechanism and specificity of the extended-spectrum SHV-2 enzyme
OverviewOverview
Bacterial beta-lactamases hydrolyze beta-lactam antibiotics such as penicillins and cephalosporins. The TEM-type class A beta-lactamase SHV-2 is a natural variant that exhibits activity against third-generation cephalosporins normally resistant to hydrolysis by class A enzymes. SHV-2 contains a single Gly238Ser change relative to the wild-type enzyme SHV-1. Crystallographic refinement of a model including hydrogen atoms gave R and R(free) of 12.4% and 15.0% for data to 0.91 A resolution. The hydrogen atom on the O(gamma) atom of the reactive Ser70 is clearly seen for the first time, bridging to the water molecule activated by Glu166. Though hydrogen atoms on the nearby Lys73 are not seen, this observation of the Ser70 hydrogen atom and the hydrogen bonding pattern around Lys73 indicate that Lys73 is protonated. These findings support a role for the Glu166-water couple, rather than Lys73, as the general base in the deprotonation of Ser70 in the acylation process of class A beta-lactamases. Overlay of SHV-2 with SHV-1 shows a significant 1-3 A displacement in the 238-242 beta-strand-turn segment, making the beta-lactam binding site more open to newer cephalosporins with large C7 substituents and thereby expanding the substrate spectrum of the variant enzyme. The OH group of the buried Ser238 side-chain hydrogen bonds to the main-chain CO of Asn170 on the Omega loop, that is unaltered in position relative to SHV-1. This structural role for Ser238 in protein-protein binding makes less likely its hydrogen bonding to oximino cephalosporins such as cefotaxime or ceftazidime.
About this StructureAbout this Structure
1N9B is a Single protein structure of sequence from Klebsiella pneumoniae. Full crystallographic information is available from OCA.
ReferenceReference
Ultrahigh resolution structure of a class A beta-lactamase: on the mechanism and specificity of the extended-spectrum SHV-2 enzyme., Nukaga M, Mayama K, Hujer AM, Bonomo RA, Knox JR, J Mol Biol. 2003 Apr 18;328(1):289-301. PMID:12684014
Page seeded by OCA on Thu Mar 20 12:53:49 2008