1htz
From Proteopedia
(New page: 200px<br /><applet load="1htz" size="450" color="white" frame="true" align="right" spinBox="true" caption="1htz, resolution 2.4Å" /> '''CRYSTAL STRUCTURE OF ...) |
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| - | [[Image:1htz.jpg|left|200px]]<br /><applet load="1htz" size=" | + | [[Image:1htz.jpg|left|200px]]<br /><applet load="1htz" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1htz, resolution 2.4Å" /> | caption="1htz, resolution 2.4Å" /> | ||
'''CRYSTAL STRUCTURE OF TEM52 BETA-LACTAMASE'''<br /> | '''CRYSTAL STRUCTURE OF TEM52 BETA-LACTAMASE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Directed evolution can be a powerful tool to predict antibiotic | + | Directed evolution can be a powerful tool to predict antibiotic resistance. Resistance involves the accumulation of mutations beneficial to the pathogen while maintaining residue interactions and core packing that are critical for preserving function. The constraint of maintaining stability, while increasing activity, drastically reduces the number of possible mutational combination pathways. To test this theory, TEM-1 beta-lactamase was evolved using a hypermutator E. coli-based directed evolution technique with cefotaxime selection. The selected mutants were compared to two previous directed evolution studies and a database of clinical isolates. In all cases, evolution resulted in the generation of the E104K/M182T/G238S combination of mutations ( approximately 500-fold increased resistance), which is equivalent to clinical isolate TEM-52. The structure of TEM-52 was determined to 2.4 A. G238S widens access to the active site by 2.8 A whereas E104K stabilizes the reorganized topology. The M182T mutation is located 17 A from the active site and appears to be a global suppressor mutation that acts to stabilize the new enzyme structure. Our results demonstrate that directed evolution coupled with structural analysis can be used to predict future mutations that lead to increased antibiotic resistance. |
==About this Structure== | ==About this Structure== | ||
| - | 1HTZ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Klebsiella_pneumoniae Klebsiella pneumoniae]. 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:// | + | 1HTZ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Klebsiella_pneumoniae Klebsiella pneumoniae]. 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=1HTZ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Klebsiella pneumoniae]] | [[Category: Klebsiella pneumoniae]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Orencia, M | + | [[Category: Orencia, M C.]] |
| - | [[Category: Stevens, R | + | [[Category: Stevens, R C.]] |
[[Category: mutant form of beta-lactamase]] | [[Category: mutant form of beta-lactamase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:04:52 2008'' |
Revision as of 11:04, 21 February 2008
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CRYSTAL STRUCTURE OF TEM52 BETA-LACTAMASE
Overview
Directed evolution can be a powerful tool to predict antibiotic resistance. Resistance involves the accumulation of mutations beneficial to the pathogen while maintaining residue interactions and core packing that are critical for preserving function. The constraint of maintaining stability, while increasing activity, drastically reduces the number of possible mutational combination pathways. To test this theory, TEM-1 beta-lactamase was evolved using a hypermutator E. coli-based directed evolution technique with cefotaxime selection. The selected mutants were compared to two previous directed evolution studies and a database of clinical isolates. In all cases, evolution resulted in the generation of the E104K/M182T/G238S combination of mutations ( approximately 500-fold increased resistance), which is equivalent to clinical isolate TEM-52. The structure of TEM-52 was determined to 2.4 A. G238S widens access to the active site by 2.8 A whereas E104K stabilizes the reorganized topology. The M182T mutation is located 17 A from the active site and appears to be a global suppressor mutation that acts to stabilize the new enzyme structure. Our results demonstrate that directed evolution coupled with structural analysis can be used to predict future mutations that lead to increased antibiotic resistance.
About this Structure
1HTZ is a Single protein structure of sequence from Klebsiella pneumoniae. Active as Beta-lactamase, with EC number 3.5.2.6 Full crystallographic information is available from OCA.
Reference
Predicting the emergence of antibiotic resistance by directed evolution and structural analysis., Orencia MC, Yoon JS, Ness JE, Stemmer WP, Stevens RC, Nat Struct Biol. 2001 Mar;8(3):238-42. PMID:11224569
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