1xpb
From Proteopedia
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| - | [[Image:1xpb.gif|left|200px]]<br /> | + | [[Image:1xpb.gif|left|200px]]<br /><applet load="1xpb" size="450" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1xpb" size="450" color="white" frame="true" align="right" spinBox="true" | + | |
caption="1xpb, resolution 1.90Å" /> | caption="1xpb, resolution 1.90Å" /> | ||
'''STRUCTURE OF BETA-LACTAMASE TEM1'''<br /> | '''STRUCTURE OF BETA-LACTAMASE TEM1'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1XPB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. 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] | + | 1XPB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. 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] Known structural/functional Site: <scene name='pdbsite=ACT:Active Site'>ACT</scene>. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1XPB OCA]. |
==Reference== | ==Reference== | ||
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[[Category: transposable element]] | [[Category: transposable element]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Dec 18 18:39:48 2007'' |
Revision as of 16:30, 18 December 2007
|
STRUCTURE OF BETA-LACTAMASE TEM1
Overview
beta-Lactamases are bacterial enzymes which catalyse the hydrolysis of the, beta-lactam ring of penicillins, cephalosporins and related compounds, thus inactivating these antibiotics. The crystal structure of the TEM1, beta-lactamase has been determined at 1.9 A resolution by the, molecular-replacement method, using the atomic coordinates of two, homologous beta-lactamase refined structures which show about 36% strict, identity in their amino-acid sequences and 1.96 A r.m.s. deviation between, equivalent Calpha atoms. The TEM1 enzyme crystallizes in space group, P2(1)2(1)2(1) and there is one molecule per asymmetric unit. The structure, was refined by simulated annealing to an R-factor of 15.6% for 15 086, reflections with I >/= 2sigma(I) in the resolution range 5.0-1.9 A. The, final crystallographic structure contains 263 amino-acid residues, one, sulfate anion in the catalytic cleft and 135 water molecules per, asymmetric unit. The folding is very similar to that of the other known, class A beta-lactamases. It consists of two domains, the first is formed, by a five-stranded beta-sheet covered by three alpha-helices on one face, and one alpha-helix on the other, the second domain contains mainly, alpha-helices. The catalytic cleft is located at the interface between the, two domains. We also report the crystallographic study of the TEM S235A, mutant. This mutation of an active-site residue specifically decreases the, acylation rate of cephalosporins. This TEM S235A mutant crystallizes under, the same conditions as the wild-type protein and its structure was refined, at 2.0 A resolution with an R value of 17.6%. The major modification is, the appearance of a water molecule near the mutated residue, which is, incompatible with the OG 235 present in the wild-type enzyme, and causes, very small perturbations in the interaction network in the active site.
About this Structure
1XPB is a Single protein structure of sequence from Escherichia coli with SO4 as ligand. Active as Beta-lactamase, with EC number 3.5.2.6 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
TEM1 beta-lactamase structure solved by molecular replacement and refined structure of the S235A mutant., Fonze E, Charlier P, To'th Y, Vermeire M, Raquet X, Dubus A, Frere JM, Acta Crystallogr D Biol Crystallogr. 1995 Sep 1;51(Pt 5):682-94. PMID:15299797
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