1lhy
From Proteopedia
(New page: 200px<br /><applet load="1lhy" size="450" color="white" frame="true" align="right" spinBox="true" caption="1lhy, resolution 2.00Å" /> '''Crystal structure of...) |
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| - | [[Image:1lhy.gif|left|200px]]<br /><applet load="1lhy" size=" | + | [[Image:1lhy.gif|left|200px]]<br /><applet load="1lhy" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1lhy, resolution 2.00Å" /> | caption="1lhy, resolution 2.00Å" /> | ||
'''Crystal structure of TEM-30 beta-Lactamase at 2.0 Angstrom'''<br /> | '''Crystal structure of TEM-30 beta-Lactamase at 2.0 Angstrom'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Widespread use of beta-lactam antibiotics has promoted the evolution of | + | Widespread use of beta-lactam antibiotics has promoted the evolution of beta-lactamase mutant enzymes that can hydrolyze ever newer classes of these drugs. Among the most pernicious mutants are the inhibitor-resistant TEM beta-lactamases (IRTs), which elude mechanism-based inhibitors, such as clavulanate. Despite much research on these IRTs, little is known about the structural bases of their action. This has made it difficult to understand how many of the resistance substitutions act as they often occur far from Ser-130. Here, three IRT structures, TEM-30 (R244S), TEM-32 (M69I/M182T), and TEM-34 (M69V), are determined by x-ray crystallography at 2.00, 1.61, and 1.52 A, respectively. In TEM-30, the Arg-244 --> Ser substitution (7.8 A from Ser-130) displaces a conserved water molecule that usually interacts with the beta-lactam C3 carboxylate. In TEM-32, the substitution Met-69 --> Ile (10 A from Ser-130) appears to distort Ser-70, which in turn causes Ser-130 to adopt a new conformation, moving its O gamma further away, 2.3 A from where the inhibitor would bind. This substitution also destabilizes the enzyme by 1.3 kcal/mol. The Met-182 --> Thr substitution (20 A from Ser-130) has no effect on enzyme activity but rather restabilizes the enzyme by 2.9 kcal/mol. In TEM-34, the Met-69 --> Val substitution similarly leads to a conformational change in Ser-130, this time causing it to hydrogen bond with Lys-73 and Lys-234. This masks the lone pair electrons of Ser-130 O gamma, reducing its nucleophilicity for cross-linking. In these three structures, distant substitutions result in accommodations that converge on the same point of action, the local environment of Ser-130. |
==About this Structure== | ==About this Structure== | ||
| - | 1LHY 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 PO4 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] Full crystallographic information is available from [http:// | + | 1LHY 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 <scene name='pdbligand=PO4:'>PO4</scene> 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] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LHY OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Minasov, G.]] | [[Category: Minasov, G.]] | ||
| - | [[Category: Shoichet, B | + | [[Category: Shoichet, B K.]] |
[[Category: Wang, X.]] | [[Category: Wang, X.]] | ||
[[Category: PO4]] | [[Category: PO4]] | ||
| Line 23: | Line 23: | ||
[[Category: x-ray structure]] | [[Category: x-ray structure]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:45:07 2008'' |
Revision as of 11:45, 21 February 2008
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Crystal structure of TEM-30 beta-Lactamase at 2.0 Angstrom
Overview
Widespread use of beta-lactam antibiotics has promoted the evolution of beta-lactamase mutant enzymes that can hydrolyze ever newer classes of these drugs. Among the most pernicious mutants are the inhibitor-resistant TEM beta-lactamases (IRTs), which elude mechanism-based inhibitors, such as clavulanate. Despite much research on these IRTs, little is known about the structural bases of their action. This has made it difficult to understand how many of the resistance substitutions act as they often occur far from Ser-130. Here, three IRT structures, TEM-30 (R244S), TEM-32 (M69I/M182T), and TEM-34 (M69V), are determined by x-ray crystallography at 2.00, 1.61, and 1.52 A, respectively. In TEM-30, the Arg-244 --> Ser substitution (7.8 A from Ser-130) displaces a conserved water molecule that usually interacts with the beta-lactam C3 carboxylate. In TEM-32, the substitution Met-69 --> Ile (10 A from Ser-130) appears to distort Ser-70, which in turn causes Ser-130 to adopt a new conformation, moving its O gamma further away, 2.3 A from where the inhibitor would bind. This substitution also destabilizes the enzyme by 1.3 kcal/mol. The Met-182 --> Thr substitution (20 A from Ser-130) has no effect on enzyme activity but rather restabilizes the enzyme by 2.9 kcal/mol. In TEM-34, the Met-69 --> Val substitution similarly leads to a conformational change in Ser-130, this time causing it to hydrogen bond with Lys-73 and Lys-234. This masks the lone pair electrons of Ser-130 O gamma, reducing its nucleophilicity for cross-linking. In these three structures, distant substitutions result in accommodations that converge on the same point of action, the local environment of Ser-130.
About this Structure
1LHY is a Single protein structure of sequence from Escherichia coli with as ligand. Active as Beta-lactamase, with EC number 3.5.2.6 Full crystallographic information is available from OCA.
Reference
The structural bases of antibiotic resistance in the clinically derived mutant beta-lactamases TEM-30, TEM-32, and TEM-34., Wang X, Minasov G, Shoichet BK, J Biol Chem. 2002 Aug 30;277(35):32149-56. Epub 2002 Jun 10. PMID:12058046
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