Role in Cell Permeability of an Essential Two-Component System inStaphylococcus aureus

Abstract

A temperature-sensitive lethal mutant of Staphylococcus aureus was found to harbor a mutation in the uncharacterized two-component histidine kinase (HK)-response regulator (RR) pair encoded by yycFG; orthologues of yycFG could be identified in the genomes of Bacillus subtilis and other gram-positive bacteria. Sequence analysis of the mutant revealed a point mutation resulting in a nonconservative change (Glu to Lys) in the regulator domain of the RR at position 63. To confirm that this signal transduction system was essential, a disrupted copy of either the RR (yycF) or the HK (yycG) was constructed with a set of suicide vectors and used to generate tandem duplications in the chromosome. Resolution of the duplications, leaving an insertion in either the yycF or the yycG coding region, was achieved only in the presence of an additional wild-type copy of the two open reading frames. Phenotypic characterization of the conditional lethal mutant showed that at permissive growth conditions, the mutant was hypersusceptible to macrolide and lincosamide antibiotics, even in the presence of the ermB resistance determinant. Other mutant phenotypes, including hypersensitivity to unsaturated long-chain fatty acids and suppression of the conditional lethal phenotype by high sucrose and NaCl concentrations, suggest that the role of the two-component system includes the proper regulation of bacterial cell wall or membrane composition. The effects of this point mutation are strongly bactericidal at the nonpermissive temperature, indicating that this pathway provides an excellent target for the identification of novel antibiotics.

Molecular characterization of Enterococcus faecalis two‐component signal transduction pathways related to environmental stresses

“…Moreover, homology searches, revealed high homologies between Err07 and the YycF protein of Bacillus subtilis and Staphylococcus aureus (69% and 63% identity, respectively) and a similar domain architecture for Ehk07 and B. subtilis and S. aureus YycG HK proteins (data not shown). Thus, the Err07-Ehk07 system probably correspond to the YycFG TCS system shown to be essential in B. subtilis and S. aureus (Fabret and Hoch, 1998;Martin et al, 1999).…”

Structure-based discovery of inhibitors of the YycG histidine kinase: New chemical leads to combat Staphylococcus epidermidis infections

“…The YycG/YycF TCS is conserved and specific for low G+C Gram-positive bacteria such as B. subtilis, S. aureus, Streptococcus pneumoniae and Listeria monocytogenes [11,12,37,38]. This TCS has been shown to be essential in B. subtilis [39] and could not be inactivated by direct mutation in S. aureus [12], and which also occurs in S. epidermidis (this work).…”

“…The YycG/YycF TCS is conserved and specific for low G+C Gram-positive bacteria such as B. subtilis, S. aureus, Streptococcus pneumoniae and Listeria monocytogenes [11,12,37,38]. This TCS has been shown to be essential in B. subtilis [39] and could not be inactivated by direct mutation in S. aureus [12], and which also occurs in S. epidermidis (this work). Moreover, several genes involved in cell-wall biosynthesis and metabolism, such as teichoic acid biosynthesis protein F [40], and cell wall synthesis protein YpfP [41] were predicted to be regulated by this TCS in S. epidermidis based on the presence of a potential YycF consensus DNA binding recognition sequence similar to the one described in B. subtilis and S. aureus [42,43], although this predicted result needs to be further verified (Qin et al, unpublished data).…”

“…Since the YycG/YycF TCS is essential for growth and survival in B. subtilis and S. aureus [11,12], its conservation in sequence and in genome organization in S. epidermidis strongly suggests that it is essential in this organism as well. To test this possibility, we explored whether the potential YycG inhibitor candidates obtained by virtual screening could inhibit bacterial growth.…”

“…Recently, the TCSs have attracted attention due to their potential as novel antibacterial targets, especially those required for regulation of bacterial growth and virulence in pathogenic microorganisms [9,10]. One TCS, YycG/ YycF, highly conserved and specific to low G+C Grampositive bacteria has been shown to be essential for Bacillus subtilis and Staphylococcus aureus survival [11,12]. Inhibitors of the YycG HK, such as synthetic imidazole and zerumbone derivatives, or aranorosinol B, obtained by screening acetone extracts from 4000 microbes, have been documented to be effective antibacterial agents against B. subtilis [13,14].…”