In Vitro and In Vivo Validation of
 ligA
 and
 tarI
 as Essential Targets in
 Staphylococcus aureus

Streker, Karin; Schäfer, Tina; Freiberg, Christoph; Brötz‐Oesterhelt, Heike; Hacker, Jörg; Labischinski, Harald; Ohlsen, Knut

doi:10.1128/aac.00548-07

Cited by 11 publications

(9 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been reported that tarI′ and tarI are both nonessential,[66] that only tarI is essential,[67] or that tarI is only essential under a certain set of growth conditions in vitro but is nonessential in an in vivo infection model. [68] Furthermore, in S. aureus Newman, seven viable transposants were isolated within tarI′J′K but none was isolated in tarIJL ,[47] suggesting that the gene duplications are not redundant. Recently, Chaudhuri et al have reported that tarI , tarJ , and tarL are essential in S. aureus .…”

Section: Gene Cluster Duplication In S Aureusmentioning

confidence: 99%

Wall Teichoic Acid Function, Biosynthesis, and Inhibition

et al. 2009

View full text Add to dashboard Cite

Section: Gene Cluster Duplication In S Aureusmentioning

confidence: 99%

Wall Teichoic Acid Function, Biosynthesis, and Inhibition

et al. 2009

View full text Add to dashboard Cite

“…The ligA gene is essential in every bacterial species examined to date, including S. aureus (13,31). In this study, however, we recovered a series of highly pyridochromanone-resistant ligA mutants of S. aureus with no obvious growth defects despite dramatic deficits in DNA ligation kinetics.…”

Section: Discussionmentioning

confidence: 79%

“…LigA is well conserved among eubacterial species, is architecturally and biochemically distinct from the ATP-dependent DNA ligases of eukaryotic cells, and has been found to be essential for bacterial viability wherever examined (13,14,15,17,31). Moreover, the DNA ligation reaction has been dissected mechanistically, mutationally, and structurally (8,20,25,26,33,34,35), and screening assays have been reported for the complete reaction cycle and for individual component steps (2,11,18).…”

Section: Admentioning

confidence: 99%

Mechanistic Assessment of DNA Ligase as an Antibacterial Target in Staphylococcus aureus

Podos

Thanassi

Pucci

2012

Antimicrob Agents Chemother

View full text Add to dashboard Cite

We report the use of a known pyridochromanone inhibitor with antibacterial activity to assess the validity of NAD ؉ -dependent DNA ligase (LigA) as an antibacterial target in Staphylococcus aureus. Potent inhibition of purified LigA was demonstrated in a DNA ligation assay (inhibition constant [K i ] ‫؍‬ 4.0 nM) and in a DNA-independent enzyme adenylation assay using full-length LigA (50% inhibitory concentration [IC 50 ] ‫؍‬ 28 nM) or its isolated adenylation domain (IC 50 ‫؍‬ 36 nM). Antistaphylococcal activity was confirmed against methicillin-susceptible and -resistant S. aureus (MSSA and MRSA) strains (MIC ‫؍‬ 1.0 g/ml). Analysis of spontaneous resistance potential revealed a high frequency of emergence (4 ؋ 10 ؊7 ) of high-level resistant mutants (MIC > 64) with associated ligA lesions. There were no observable effects on growth rate in these mutants. N ADϩ -dependent DNA ligase (LigA) has been identified by numerous authors as an attractive potential target for broadspectrum antibacterial chemotherapy (7,23). LigA is well conserved among eubacterial species, is architecturally and biochemically distinct from the ATP-dependent DNA ligases of eukaryotic cells, and has been found to be essential for bacterial viability wherever examined (13,14,15,17,31). Moreover, the DNA ligation reaction has been dissected mechanistically, mutationally, and structurally (8,20,25,26,33,34,35), and screening assays have been reported for the complete reaction cycle and for individual component steps (2,11,18).DNA ligation activities are essential for multiple DNA processes in replication and repair, including the joining of Okazaki fragments into a continuous strand during chromosomal DNA replication. Enzymatically, DNA ligation proceeds via three successive adenylyl transfer steps (Fig. 1) (32): first, DNA-independent covalent adenylation of the catalytic lysine by the NAD ϩ substrate; second, adenylyl transfer to the free 5= phosphate at the nicked DNA ligation site; and third, the covalent sealing of the DNA nick with concomitant AMP release. Biochemical functions of distinct domains in the modular enzyme structure have been assigned to particular reaction steps. The DNA-independent adenylyl transfer activity resides within the amino-terminal adenylation domain, which comprises an amino-terminal Ia region that is specific to NAD ϩ -dependent DNA ligases and a nucleotidyl transferase (NTase) region that is universal among DNA and RNA ligases. The subsequent coupling of adenylation to DNA ligation depends upon downstream DNA-binding domains, which include an oligonucleotide-binding fold (OB fold) and a helix-hairpin-helix (HhH) domain. Structural studies of the adenylation domain have revealed conformational transitions that accompany the adenylation cycle (8), and structural study of the full-length enzyme bound to DNA-adenylate has identified specific contacts between the DNA-binding domains and the DNA duplex substrate near the nicked ligation site (20).Numerous LigA inhibitors have been reported to date, including ary...

show abstract

“…Validation of the essential nature of a previously uninvestigated target for all species of the intended bacterial spectrum in vitro as well as in the host during the infection process is mandatory and methodologically highly challenging, especially if at the beginning of a screening campaign a model target inhibitor is not available. Techniques for in vivo target validation have been described but only sporadically applied [32,33]. This makes targets and metabolic pathways that have been validated by therapeutically applied anti biotics especially valuable.…”

Section: Lessons From Targetsmentioning

confidence: 98%

Postgenomic Strategies in Antibacterial Drug Discovery

Brötz‐Oesterhelt

Saß

2010

Future Microbiol.

View full text Add to dashboard Cite

During the last decade the field of antibacterial drug discovery has changed in many aspects including bacterial organisms of primary interest, discovery strategies applied and pharmaceutical companies involved. Target-based high-throughput screening had been disappointingly unsuccessful for antibiotic research. Understanding of this lack of success has increased substantially and the lessons learned refer to characteristics of targets, screening libraries and screening strategies. The 'genomics' approach was replaced by a diverse array of discovery strategies, for example, searching for new natural product leads among previously abandoned compounds or new microbial sources, screening for synthetic inhibitors by targeted approaches including structure-based design and analyses of focused libraries and designing resistance-breaking properties into antibiotics of established classes. Furthermore, alternative treatment options are being pursued including anti-virulence strategies and immunotherapeutic approaches. This article summarizes the lessons learned from the genomics era and describes discovery strategies resulting from that knowledge.

show abstract

In Vitro and In Vivo Validation of ligA and tarI as Essential Targets in Staphylococcus aureus

Cited by 11 publications

References 15 publications

Wall Teichoic Acid Function, Biosynthesis, and Inhibition

Wall Teichoic Acid Function, Biosynthesis, and Inhibition

Mechanistic Assessment of DNA Ligase as an Antibacterial Target in Staphylococcus aureus

Postgenomic Strategies in Antibacterial Drug Discovery

Contact Info

Product

Resources

About