1r9c
From Proteopedia
(New page: 200px<br /><applet load="1r9c" size="450" color="white" frame="true" align="right" spinBox="true" caption="1r9c, resolution 1.83Å" /> '''Crystal Structure of...) |
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| - | [[Image:1r9c.gif|left|200px]]<br /><applet load="1r9c" size=" | + | [[Image:1r9c.gif|left|200px]]<br /><applet load="1r9c" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1r9c, resolution 1.83Å" /> | caption="1r9c, resolution 1.83Å" /> | ||
'''Crystal Structure of Fosfomycin Resistance Protein FosX from Mesorhizobium Loti'''<br /> | '''Crystal Structure of Fosfomycin Resistance Protein FosX from Mesorhizobium Loti'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Microbial resistance to the antibiotic fosfomycin [(1R,2S)-epoxypropylphosphonic acid, 1] is known to be mediated by thiol transferase enzymes FosA and FosB, which catalyze the addition of glutathione and | + | Microbial resistance to the antibiotic fosfomycin [(1R,2S)-epoxypropylphosphonic acid, 1] is known to be mediated by thiol transferase enzymes FosA and FosB, which catalyze the addition of glutathione and l-cysteine to C1 of the oxirane, respectively. A probe of the microbial genome database reveals a related group of enzymes (FosX). The genes mlr3345 from Mesorhizobium loti and lmo1702 from Listeria monocytogenes were cloned and the proteins expressed. This heretofore unrecognized group of enzymes is shown to catalyze the Mn(II)-dependent addition of water to C1 of the oxirane. The ability of each enzyme to confer resistance in Escherichia coli is correlated with their catalytic efficiency, such that the M. loti protein confers low resistance while the Listeria enzyme confers very robust resistance. The crystal structure of the FosX from M. loti was solved at a resolution of 1.83 A. The structure reveals an active-site carboxylate (E44) located about 5 A from the expected position of the substrate that appears to be poised to participate in catalysis. Single turnover experiments in H218O and kinetic analysis of the E44G mutant of the FosX enzymes indicate that the carboxylate of E44 acts as a general base in the direct addition of water to 1. The FosX from M. loti also catalyzes the addition of glutathione to the antibiotic. The catalytic promiscuity and low efficiency of the M. loti protein suggest that it may be an intermediate in the evolution of clinically relevant fosfomycin resistance proteins such as the FosX from Listeria monocytogenese. |
==About this Structure== | ==About this Structure== | ||
| - | 1R9C is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mesorhizobium_loti Mesorhizobium loti] with MN as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Dimethylallyltranstransferase Dimethylallyltranstransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.5.1.1 2.5.1.1] Full crystallographic information is available from [http:// | + | 1R9C is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mesorhizobium_loti Mesorhizobium loti] with <scene name='pdbligand=MN:'>MN</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Dimethylallyltranstransferase Dimethylallyltranstransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.5.1.1 2.5.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1R9C OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Mesorhizobium loti]] | [[Category: Mesorhizobium loti]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Armstrong, R | + | [[Category: Armstrong, R N.]] |
| - | [[Category: Fillgrove, K | + | [[Category: Fillgrove, K L.]] |
| - | [[Category: Newcomer, M | + | [[Category: Newcomer, M E.]] |
[[Category: Pakhomova, S.]] | [[Category: Pakhomova, S.]] | ||
[[Category: MN]] | [[Category: MN]] | ||
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[[Category: mn binding]] | [[Category: mn binding]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:48:22 2008'' |
Revision as of 12:48, 21 February 2008
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Crystal Structure of Fosfomycin Resistance Protein FosX from Mesorhizobium Loti
Overview
Microbial resistance to the antibiotic fosfomycin [(1R,2S)-epoxypropylphosphonic acid, 1] is known to be mediated by thiol transferase enzymes FosA and FosB, which catalyze the addition of glutathione and l-cysteine to C1 of the oxirane, respectively. A probe of the microbial genome database reveals a related group of enzymes (FosX). The genes mlr3345 from Mesorhizobium loti and lmo1702 from Listeria monocytogenes were cloned and the proteins expressed. This heretofore unrecognized group of enzymes is shown to catalyze the Mn(II)-dependent addition of water to C1 of the oxirane. The ability of each enzyme to confer resistance in Escherichia coli is correlated with their catalytic efficiency, such that the M. loti protein confers low resistance while the Listeria enzyme confers very robust resistance. The crystal structure of the FosX from M. loti was solved at a resolution of 1.83 A. The structure reveals an active-site carboxylate (E44) located about 5 A from the expected position of the substrate that appears to be poised to participate in catalysis. Single turnover experiments in H218O and kinetic analysis of the E44G mutant of the FosX enzymes indicate that the carboxylate of E44 acts as a general base in the direct addition of water to 1. The FosX from M. loti also catalyzes the addition of glutathione to the antibiotic. The catalytic promiscuity and low efficiency of the M. loti protein suggest that it may be an intermediate in the evolution of clinically relevant fosfomycin resistance proteins such as the FosX from Listeria monocytogenese.
About this Structure
1R9C is a Single protein structure of sequence from Mesorhizobium loti with as ligand. Active as Dimethylallyltranstransferase, with EC number 2.5.1.1 Full crystallographic information is available from OCA.
Reference
Mechanistic diversity of fosfomycin resistance in pathogenic microorganisms., Fillgrove KL, Pakhomova S, Newcomer ME, Armstrong RN, J Am Chem Soc. 2003 Dec 24;125(51):15730-1. PMID:14677948
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