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Updated: Jul 30, 2026
Quantification of Bacterial Histidine Kinase Autophosphorylation Using a Nitrocellulose Binding Assay
Published on: January 11, 2017
Antifungal properties and target evaluation of three putative bacterial histidine kinase inhibitors
R J Deschenes1, H Lin, A D Ault
1Departments of Biochemistry and Biological Sciences, University of Iowa, Iowa City, Iowa 52242, USA. robert-deschenes@uiowa.edu
Abstract:
Histidine protein kinases have been explored as potential antibacterial drug targets. The recent identification of two-component histidine kinases in fungi has led us to investigate the antifungal properties of three bacterial histidine kinase inhibitors (RWJ-49815, RWJ-49968, and RWJ-61907). All three compounds were found to inhibit growth of the Saccharomyces cerevisiae and Candida albicans strains, with MICs ranging from 1 to 20 microg/ml. However, deletion of SLN1, the only histidine kinase in S. cerevisiae, did not alter drug efficacy. In vitro kinase assays were performed by using the Sln1 histidine kinase purified from bacteria as a fusion protein to glutathione S-transferase. RWJ-49815 and RWJ-49968 inhibited kinase a 50% inhibitory concentration of 10 microM, whereas RWJ-61907 failed to inhibit at concentrations up to 100 microM. Based on these results, we conclude that these compounds have antifungal properties; however, their mode of action appears to be independent of histidine kinase inhibition.
Insights
Three bacterial histidine kinase inhibitors show antifungal properties against yeast strains. However, their mechanism of action does not involve inhibiting histidine kinase activity.
Area of Science:
- Mycology
- Biochemistry
- Pharmacology
Background:
- Histidine protein kinases are potential antibacterial targets.
- Two-component histidine kinases have been identified in fungi.
- Bacterial histidine kinase inhibitors were investigated for antifungal activity.
Purpose of the Study:
- To evaluate the antifungal properties of three bacterial histidine kinase inhibitors: RWJ-49815, RWJ-49968, and RWJ-61907.
- To determine if these compounds inhibit fungal growth through histidine kinase inhibition.
Main Methods:
- Compounds were tested against Saccharomyces cerevisiae and Candida albicans strains.
- Minimum inhibitory concentrations (MICs) were determined.
- In vitro kinase assays were performed using purified Sln1 histidine kinase.
Main Results:
- All three compounds inhibited the growth of S. cerevisiae and C. albicans, with MICs between 1-20 microg/ml.
- Deletion of the S. cerevisiae SLN1 histidine kinase did not affect drug efficacy.
- RWJ-49815 and RWJ-49968 inhibited kinase activity at 10 microM, while RWJ-61907 did not.
Conclusions:
- The tested compounds possess antifungal properties.
- The antifungal mode of action of these compounds is independent of histidine kinase inhibition.
