Antibacterial Agent Discovery Using Thymidylate Synthase Biolibrary Screening

Abstract

Thymidylate synthase (TS, ThyA) catalyzes the reductive methylation of 2'-deoxyuridine 5'-monophosphate to 2'-deoxythymidine 5'-monophosphate, an essential precursor for DNA synthesis. A specific inhibition of this enzyme induces bacterial cell death. As a second round lead optimization design, new 1,2-naphthalein derivatives have been synthesized and tested against a TS-based biolibrary, including human thymidylate synthase (hTS). Docking studies have been performed to rationalize the experimentally observed affinity profiles of 1,2-naphthalein compounds toward Lactobacillus casei TS and hTS. The best TS inhibitors have been tested against a number of clinical isolates of Gram-positive-resistant bacterial strains. Compound 3,3-bis(3,5-dibromo-4-hydroxyphenyl)-1H,3H-naphtho[1,2-c]furan-1-one (5) showed significant antibacterial activity, no in vitro toxicity, and dose-response effects against Staphylococcus epidermidis (MIC=0.5-2.5 microg/mL) clinical isolate strains, which are resistant to at least 17 of the best known antibacterial agents, including vancomycin. So far this compound can be regarded as a leading antibacterial agent.

Biological evaluation of MR36, a novel non-polyglutamatable thymidylate synthase inhibitor that blocks cell cycle progression in melanoma cell lines

“…This aggregation induces the recruitment of FADD (3) and procaspase-8 activation. Caspase-8 activation (4) leads to caspase-3 cleavage (11), which initiates multiple proapoptotic processes, including CAD stimulation (12) and DNA cleavage (13). At the same time, in the mitochondrial pathway, proapoptotic proteins form pores in the mitochondria.…”

“…This process then releases apoptogenic factors, including cytochrome C (8), APAF1, and caspase-9, from the mitochondrial intermembrane space (9). These factors form the apoptosome (10), which stimulates apoptosis through caspase-3 cleavage (11), CAD stimulation (12) and DNA cleavage (13). Data from the present study suggest that MR36 regulates the levels of the known cell cycle regulator cyclin D and the cell cycle inhibitors p21 (5) and pRb (6), resulting in cell cycle arrest and apoptosis (13) pemetrexed, and ZD9331.…”

“…dTMP is then converted to a triphosphate by DNA polymerase and is incorporated into DNA [12]. The reaction is assisted by N5,N10-methylenetetrahydrofolate (mTHF), a co-substrate for the catalyzed reaction, and is the only source of dTMP.…”

Antibiotic Sensitivity Profiles Determined with an Escherichia coli Gene Knockout Collection: Generating an Antibiotic Bar Code

“…The spread of resistance (2,21,51) has long stimulated efforts to find new antibiotics by a variety of methods, such as altering existing antibiotics, screening chemical (18) or peptide (32,43) libraries for specific inhibitors (18), or targeting new proteins or processes (11,32,35,47,58). Recent efforts also have involved detecting new targets through genomics (66,67), such as bioinformatics screening for novel producers of peptide antimicrobials (8) and finding new sources of antibiotics via metagenomics (68).…”

Noncovalent Intermediate of Thymidylate Synthase: Fact or Fiction?

“…1 Accordingly, targeting TSase remains one of the most successful approaches in cancer treatment, 2 and one of the prospective approaches in antibacterial chemotherapy. 3 Structural analogs of dUMP (e.g., fluoropyrimidines) and CH 2 H 4 F (e.g., antifolates) are well-established drugs targeting TSase. Despite many therapeutic advantages, these agents lead to toxicity and development of acquired resistance in cells.…”