RRC ID 41257
Author Fakhruzzaman M, Inukai Y, Yanagida Y, Kino H, Igarashi M, Eguchi Y, Utsumi R.
Title Study on in vivo effects of bacterial histidine kinase inhibitor, Waldiomycin, in Bacillus subtilis and Staphylococcus aureus.
Journal J. Gen. Appl. Microbiol.
Abstract Two-component signal transduction systems (TCSs) represent one of the primary means by which bacteria sense and respond to changes in their environment, both intra- and extracellular. The highly conserved WalK (histidine kinase)/WalR (response regulator) TCS is essential for cell wall metabolism of low G+C Gram-positive bacteria and acts as a master regulatory system in controlling and coordinating cell wall metabolism with cell division. Waldiomycin, a WalK inhibitor, has been discovered by screening metabolites from actinomycetes and belongs to the family of angucycline antibiotics. In the present study, we have shown that waldiomycin inhibited autophosphorylation of WalK histidine kinases in vitro from Bacillus subtilis, Staphylococcus aureus, Enterococcus faecalis, and Streptococcus mutans at half-maximal inhibitory concentrations of 10.2, 8.8, 9.2, and 25.8 μM, respectively. Quantitative RT-PCR studies of WalR regulon genes have suggested that waldiomycin repressed the WalK/WalR system in B. subtilis and S. aureus cells. Morphology of waldiomycin-treated S. aureus cells displayed increased aggregation instead of proper cellular dissemination. Furthermore, autolysis profiles of S. aureus cells revealed that waldiomycin-treated cells were highly resistant to Triton X-100- and lysostaphin-induced lysis. These phenotypes are consistent with those of cells starved for the WalK/WalR system, indicating that waldiomycin inhibited the autophosphorylation activity of WalK in cells. We have also confirmed that waldiomycin inhibits WalK autophosphorylation in vivo by actually observing the phosphorylated WalK ratio in cells using Phos-tag SDS-PAGE. The results of our current study strongly suggest that waldiomycin targets WalK histidine kinases and inhibits the WalR regulon genes expression, thereby affecting both cell wall metabolism and cell division.
Volume 61(5)
Pages 177-84
Published 2015
DOI 10.2323/jgam.61.177
PMID 26582287
MeSH Bacillus subtilis / drug effects Bacillus subtilis / enzymology* Cell Division / drug effects Cell Wall / drug effects Cell Wall / metabolism Enterococcus faecalis / drug effects Enterococcus faecalis / enzymology Enzyme Inhibitors / pharmacology* Gene Expression Profiling Histidine Kinase Protein Kinases / metabolism* Quinones / pharmacology* Regulon Staphylococcus aureus / drug effects Staphylococcus aureus / enzymology* Streptococcus mutans / drug effects Streptococcus mutans / enzymology
IF 1.172
Times Cited 2
General Microbes JCM 5803