Skip Navigation
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

National Institute of Environmental Health Sciences

Use this QR code to view the newest version of this document
Use this QR code to view the newest version of this document

Your Environment. Your Health.

Publication Detail

Title: Phosphonoformate: a minimal transition state analogue inhibitor of the fosfomycin resistance protein, FosA.

Authors: Rigsby, Rachel E; Rife, Chris L; Fillgrove, Kerry L; Newcomer, Marcia E; Armstrong, Richard N

Published In Biochemistry, (2004 Nov 2)

Abstract: Fosfomycin [(1R,2S)-epoxypropylphosphonic acid] is a simple phosphonate found to have antibacterial activity against both Gram-positive and Gram-negative microorganisms. Early resistance to the clinical use of the antibiotic was linked to a plasmid-encoded resistance protein, FosA, that catalyzes the addition of glutathione to the oxirane ring, rendering the antibiotic inactive. Subsequent studies led to the discovery of a genomically encoded homologue in the pathogen Pseudomonas aeruginosa. The proteins are Mn(II)-dependent enzymes where the metal is proposed to act as a Lewis acid stabilizing the negative charge that develops on the oxirane oxygen in the transition state. Several simple phosphonates, including the antiviral compound phosphonoformate (K(i) = 0.4 +/- 0.1 microM, K(d) approximately 0.2 microM), are shown to be inhibitors of FosA. The crystal structure of FosA from P. aeruginosa with phosphonoformate bound in the active site has been determined at 0.95 A resolution and reveals that the inhibitor forms a five-coordinate complex with the Mn(II) center with a geometry similar to that proposed for the transition state of the reaction. Binding studies show that phosphonoformate has a near-diffusion-controlled on rate (k(on) approximately 10(7)-10(8) M(-1) s(-1)) and an off rate (k(off) = 5 s(-1)) that is slower than that for fosfomycin (k(off) = 30 s(-1)). Taken together, these data suggest that the FosA-catalyzed reaction has a very early transition state and phosphonoformate acts as a minimal transition state analogue inhibitor.

PubMed ID: 15504029 Exiting the NIEHS site

MeSH Terms: Bacterial Proteins/antagonists & inhibitors*; Bacterial Proteins/chemistry*; Bacterial Proteins/isolation & purification; Binding Sites; Catalysis; Crystallization; Crystallography, X-Ray; Drug Resistance, Bacterial*; Foscarnet/chemistry*; Fosfomycin/chemistry*; Glutathione Transferase/antagonists & inhibitors*; Glutathione Transferase/chemistry*; Glutathione Transferase/isolation & purification; Kinetics; Manganese/chemistry; Phosphonic Acids/chemistry; Pseudomonas aeruginosa/chemistry*; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.

Back
to Top