Inhibition of Yersinia pestisDNA adenine methyltransferase in vitro by a stibonic acid compound: identification of a potential novel class of antimicrobial agents

Abstract

BACKGROUND AND PURPOSEMultiple antibiotic resistant strains of plague are emerging, driving a need for the development of novel antibiotics effective against Yersinia pestis. DNA adenine methylation regulates numerous fundamental processes in bacteria and alteration of DNA adenine methlytransferase (Dam) expression is attenuating for several pathogens, including Y. pestis. The lack of a functionally similar enzyme in humans makes Dam a suitable target for development of novel therapeutics for plague. EXPERIMENTAL APPROACHCompounds were evaluated for their ability to inhibit Dam activity in a high-throughput screening assay. DNA was isolated from Yersinia grown in the presence of lead compounds and restricted to determine the effect of inhibitors on DNA methylation. Transcriptional analysis was undertaken to determine the effect of an active inhibitor on virulence-associated phenotypes. KEY RESULTSWe have identified a series of aryl stibonic acids which inhibit Dam in vitro. The most active, 4-stibonobenzenesulfonic acid, exhibited a competitive mode of inhibition with respect to DNA and a Ki of 6.46 nM. One compound was found to inhibit DNA methylation in cultured Y. pestis. The effects of this inhibition on the physiology of the cell were widespread, and included altered expression of known virulence traits, including iron acquisition and Type III secretion. CONCLUSIONS AND IMPLICATIONSWe have identified a novel class of potent Dam inhibitors. Treatment of bacterial cell cultures with these inhibitors resulted in a decrease in DNA methylation. Expression of virulence factors was affected, suggesting these inhibitors may attenuate bacterial infectivity and function as antibiotics. AbbreviationsAdoHcy, S-adenosylhomocysteine; A m , N6-methyladenine; D, dabcyl quencher; Dam, DNA adenine methyltransferase

A comparative analysis of methylome profiles of Campylobacter jejuni sheep abortion isolate and gastroenteric strains using PacBio data

“…This also brings to question if methylation is a key evolutionary event for other Campylobacter species as it may be for IA3902, 11168, and 81-176. In practical applications, uncovering the mechanisms for methylation on Campylobacter gene expression would make DNA methylation a promising drug target against diseases of Campylobacter and related organisms, as has been exploited in other bacteria (Mashhoon et al, 2004 ; Feder et al, 2008 ; Mckelvie et al, 2013 ).…”

A role for the bacterial GATC methylome in antibiotic stress survival

“…The finding that genomic GATC methylation supports β-lactam stress survival in E. coli evokes the possibility of targeting Dam to therapeutically potentiate antibiotic drug activity. Dam is an attractive target as it lacks mammalian homologs but is conserved in several enteric pathogens 57 – 59 . Furthermore, because muliple drugs can induce mutagenic responses in bacteria 9 , 12 , 55 , 60 – 62 , treatment with antibiotics other than β-lactams should also be potentiated in the absence of GATC methylation.…”

The methylome of the gut microbiome: disparate Dam methylation patterns in intestinal Bacteroides dorei

“…The GATC methylation system has been shown to increase virulence in Salmonella enterica serovar Typhimurium, Vibrio cholerae , Yersinia pestis , and Yersinia pseudotuberculosis (Heithoff et al, 1999 ; Julio et al, 2001 , 2002 ; Robinson et al, 2005 ). As a result, significant efforts have been made in recent years to design antibiotics that inhibit DamMT (Mashhoon et al, 2004 , 2006 ; Hobley et al, 2012 ; McKelvie et al, 2013 ).…”