PMID:3881084
| Citation |
Sastry, SS and Jayaraman, R (1985) Inhibitors of nitrofuran reduction in Escherichia coli: evidence for their existence, partial purification, binding of nitrofurantoin in vitro, and implications for nitrofuran resistance. Arch. Biochem. Biophys. 236:252-9 |
|---|---|
| Abstract |
Nitrofurantoin (NF)-resistant mutants of Escherichia coli were isolated as described previously (18). One of the mutants (SSJ-2) was found to possess NF reductase activity equal to that of its parent (E. coli KL16). Two NF-resistant transductional derivatives, SSJ-2A and SSJ-2B, were isolated using SSJ-2 as the donor. SSJ-2 was found to be a double mutant carrying two mutations, nfnA and nfnB, while SSJ-2A (nfnA) and SSJ-2B (nfnB) carried these mutations individually. Heated extracts from SSJ-2A and SSJ-2B were found to inhibit the reduction of NF by unheated extracts of the NF-sensitive strain E. coli KL16 in vitro. Unheated extracts of these mutants reduced NF poorly relative to E. coli KL16. The poor reduction of NF by unheated extracts of SSJ-2A and SSJ-2B was greatly stimulated by heated extracts of SSJ-2B and SSJ-2A, respectively, and also by heated extracts of E. coli KL16. When heated extracts of SSJ-2A and SSJ-2B were mixed in a particular ratio and added to unheated extracts of E. coli KL16 they lost their inhibitory activity. Two proteins, designated inhibitor A and inhibitor B, have been partially purified from heated extracts of SSJ-2B and SSJ-2A, respectively. Their respective molecular weights, as determined by gel chromatography, were 37,000 and 20,500. The two inhibitors bound nitrofurantoin in vitro, and the NF-binding ability was lost when mixed in the molar ration of 3/1 (B/A). These observations were rationalized in terms of a hypothesis which explains (i) maximal NF reduction in wild-type cells, (ii) maximal NF reduction of nfnA-nfnB- double mutant, and (iii) poor NF reduction in nfnA- or nfnB- single mutants. The possible role of these inhibitors in nitrofurantoin resistance is also discussed. |
| Links | |
| Keywords |
Drug Resistance, Microbial; Escherichia coli/drug effects; Escherichia coli/genetics; Escherichia coli/metabolism; Hot Temperature; Mutation; Nitrofurantoin/metabolism; Nitrofurantoin/pharmacology; Nitroreductases; Oxidation-Reduction; Oxidoreductases/antagonists & inhibitors; Protein Binding |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.