GONUTS has been updated to MW1.31 Most things seem to be working but be sure to report problems.

Have any questions? Please email us at ecoliwiki@gmail.com

PMID:22752166

From GONUTS
Jump to: navigation, search
Citation

Tao, W, Lee, MH, Wu, J, Kim, NH, Kim, JC, Chung, E, Hwang, EC and Lee, SW (2012) Inactivation of chloramphenicol and florfenicol by a novel chloramphenicol hydrolase. Appl. Environ. Microbiol. 78:6295-301

Abstract

Chloramphenicol and florfenicol are broad-spectrum antibiotics. Although the bacterial resistance mechanisms to these antibiotics have been well documented, hydrolysis of these antibiotics has not been reported in detail. This study reports the hydrolysis of these two antibiotics by a specific hydrolase that is encoded by a gene identified from a soil metagenome. Hydrolysis of chloramphenicol has been recognized in cell extracts of Escherichia coli expressing a chloramphenicol acetate esterase gene, estDL136. A hydrolysate of chloramphenicol was identified as p-nitrophenylserinol by liquid chromatography-mass spectroscopy and proton nuclear magnetic resonance spectroscopy. The hydrolysis of these antibiotics suggested a promiscuous amidase activity of EstDL136. When estDL136 was expressed in E. coli, EstDL136 conferred resistance to both chloramphenicol and florfenicol on E. coli, due to their inactivation. In addition, E. coli carrying estDL136 deactivated florfenicol faster than it deactivated chloramphenicol, suggesting that EstDL136 hydrolyzes florfenicol more efficiently than it hydrolyzes chloramphenicol. The nucleotide sequences flanking estDL136 encode proteins such as amidohydrolase, dehydrogenase/reductase, major facilitator transporter, esterase, and oxidase. The most closely related genes are found in the bacterial family Sphingomonadaceae, which contains many bioremediation-related strains. Whether the gene cluster with estDL136 in E. coli is involved in further chloramphenicol degradation was not clear in this study. While acetyltransferases for chloramphenicol resistance and drug exporters for chloramphenicol or florfenicol resistance are often detected in numerous microbes, this is the first report of enzymatic hydrolysis of florfenicol resulting in inactivation of the antibiotic.

Links

PubMed PMC3416615 Online version:10.1128/AEM.01154-12

Keywords

Amidohydrolases/genetics; Amidohydrolases/isolation & purification; Amidohydrolases/metabolism; Anti-Bacterial Agents/metabolism; Anti-Bacterial Agents/pharmacology; Chloramphenicol/metabolism; Chloramphenicol/pharmacology; Chromatography, Liquid; Cloning, Molecular; DNA, Bacterial/chemistry; DNA, Bacterial/genetics; Escherichia coli/genetics; Escherichia coli/metabolism; Gene Expression; Hydrolysis; Mass Spectrometry; Metagenome; Molecular Sequence Data; Sequence Analysis, DNA; Soil Microbiology; Thiamphenicol/analogs & derivatives; Thiamphenicol/metabolism; Thiamphenicol/pharmacology

Significance

Annotations

Gene product Qualifier GO Term Evidence Code with/from Aspect Extension Notes Status

9BACT:I6N3G4

GO:0016810: hydrolase activity, acting on carbon-nitrogen (but not peptide) bonds

ECO:0000314:

F

Figure 1 shows degradation of chloramphenicol in the presence of cell extract containing DL136. Figure 2 shows the mass spec and NMR for both the hydrosylate and the nitrophenylserinol standard. These are identical, showing that DL136 hydrolyzed the amide bond in chloramphenicol.

complete
CACAO 10677

Notes

See also

References

See Help:References for how to manage references in GONUTS.