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Evaluating LC-MS/MS To Measure Accumulation of Compounds within Bacteria

Authors :
Zhengqi Ye
Ramkumar Iyer
Annette Ferrari
Tiansheng Wang
Alice L. Erwin
M. Angela Tanudra
Christopher L Brummel
Hong Gao
Leonard R. Duncan
Hong Tsao
Source :
ACS infectious diseases. 4(9)
Publication Year :
2018

Abstract

A general method for determining bacterial uptake of compounds independent of antibacterial activity would be a valuable tool in antibacterial drug discovery. LC-MS/MS assays have been described, but it has not been shown whether the data can be used directly to inform medicinal chemistry. We describe the evaluation of an LC-MS/MS assay measuring association of compounds with bacteria, using a set of over a hundred compounds (inhibitors of NAD-dependent DNA ligase, LigA) for which in vitro potency and antibacterial activity had been determined. All compounds were active against an efflux-deficient strain of Escherichia coli with reduced LigA activity ( E. coli ligA251 Δ tolC). Testing a single compound concentration and incubation time, we found that, for equipotent compounds, LC-MS/MS values were not predictive of antibacterial activity. This indicates that measured bacteria-associated compound was not necessarily exposed to the target enzyme. Our data suggest that, while exclusion from bacteria is a major reason for poor antibacterial activity of potent compounds, the distribution of compound within the bacterial cell may also be a problem. The relative importance of these factors is likely to vary from one chemical series to another. Our observations provide directions for further study of this difficult issue.

Details

ISSN :
23738227
Volume :
4
Issue :
9
Database :
OpenAIRE
Journal :
ACS infectious diseases
Accession number :
edsair.doi.dedup.....8d6bc4babe1baee4b3ed753a712f7433