1NKI

CRYSTAL STRUCTURE OF THE FOSFOMYCIN RESISTANCE PROTEIN A (FOSA) CONTAINING BOUND PHOSPHONOFORMATE

Summary for 1NKI

• Entry DOI: 10.2210/pdb1nki/pdb
• Related: 1LQK 1LQO 1LQP
• Descriptor: probable fosfomycin resistance protein, POTASSIUM ION, MANGANESE (II) ION, ... (5 entities in total)
• Functional Keywords: potassium binding loop, manganese binding, transferase
• Biological source: Pseudomonas aeruginosa
• Cellular location: Cytoplasm : Q9I4K6
• Total number of polymer chains: 2
• Total formula weight: 30726.09

Authors

Rife, C.L.,Pharris, R.E.,Newcomer, M.E.,Armstrong, R.N. (deposition date: 2003-01-03, release date: 2004-01-13, Last modification date: 2023-08-16)

Primary citation

Rigsby, R.E.,Rife, C.L.,Fillgrove, K.L.,Newcomer, M.E.,Armstrong, R.N.
Phosphonoformate: a minimal transition state analogue inhibitor of the fosfomycin resistance protein, FosA.
Biochemistry, 43:13666-13673, 2004

PubMed 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: 15504029
DOI: 10.1021/bi048767h

Experimental method

X-RAY DIFFRACTION (0.95 Å)