Database accession: MF7000459
Name: Fosfomycin Resistance Protein A (FosA) with phosphonoformate
PDB ID: 1nki
Experimental method: X-ray (0.95 Å)
Assembly: Homodimer
Source organism: Pseudomonas aeruginosa
Primary publication of the structure:
Rigsby RE, Rife CL, Fillgrove KL, Newcomer ME, Armstrong RN
Phosphonoformate: a minimal transition state analogue inhibitor of the fosfomycin resistance protein, FosA.
(2004) Biochemistry 43: 13666-73
PMID: 15504029
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.
Annotations from the GeneOntology database. Only terms that fit at least two of the interacting proteins are shown. Molecular function:
glutathione transferase activity glutathione transferase activity
metal ion binding metal ion binding
Biological process:
response to antibiotic response to antibiotic
Cellular component:
cytoplasm cytoplasm
Structural annotations of the participating protein chains.Entry contents: 2 distinct polypeptide molecules
Chains: A, B
Notes: All chains according to the most probable oligomerization state stored in PDBe were considered.
Number of unique protein segments: 1
Name: Glutathione transferase FosA
Source organism: Pseudomonas aeruginosa
Length: 135 residues
Sequence:Sequence according to the corresponding UniProt protein segmentMLTGLNHLTLAVADLPASIAFYRDLLGFRLEARWDQGAYLELGSLWLCLSREPQYGGPAADYTHYAFGIAAADFARFAAQLRAHGVREWKQNRSEGDSFYFLDPDGHRLEAHVGDLRSRLAACRQAPYAGMRFAD
UniProtKB AC: Q9I4K6 (positions: 1-134)
Coverage: 99%
Name: Glutathione transferase FosA
Source organism: Pseudomonas aeruginosa
Length: 135 residues
Sequence:Sequence according to the corresponding UniProt protein segmentMLTGLNHLTLAVADLPASIAFYRDLLGFRLEARWDQGAYLELGSLWLCLSREPQYGGPAADYTHYAFGIAAADFARFAAQLRAHGVREWKQNRSEGDSFYFLDPDGHRLEAHVGDLRSRLAACRQAPYAGMRFAD
UniProtKB AC: Q9I4K6 (positions: 1-134)
Coverage: 99%
Evidence demonstrating that the participating proteins are unstructured prior to the interaction and their folding is coupled to binding. Representative domain in related structures: Glyoxalase/Bleomycin resistance protein/Dioxygenase superfamily
Evidence level: Indirect evidence
Evidence coverage: The full structure participates in mutual synergistic folding.
Complex Evidence:
The VOC superfamily of metalloenzymes is characterized by a three-dimensional domain-swapped arrangement of tandem βαβββ-motifs (PMID:24447055). The original gene duplication event led to the βαβββ tandem structure, which appears to require dimerization for stability. Two different forms of domain-swapped dimers may coexist in solution (PMID:12121648) in which both subunits of the homodimer participate in coordination of each metal ion and formation of the U-shaped active sites in the enzyme (PMID:24004181). The complex is predominantly dimeric in solution (gel filtration) (PMID:12121648).
Chain A:
N/A
Chain B:
N/A
Surface and contacts features:
Structures from the PDB that contain the same number of proteins, and the proteins from the two structures show a sufficient degree of pairwise similarity, i.e. they belong to the same UniRef90 cluster (the full proteins exhibit at least 90% sequence identity) and convey roughly the same region to their respective interactions (the two regions from the two proteins share a minimum of 70% overlap). Download the CIF file (.cif)
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