Search

The protozoan parasite Trichomonas vaginalis (Tv) causes trichomoniasis, the most common non‐viral sexually transmitted infection in the world. Although Tv has been linked to significant health complications, only two closely related 5‐nitroimidazole drugs are approved for its treatment. The emergence of resistance to these drugs and lack of alternative treatment options poses an increasing threat to public health, making development of novel anti‐Trichomonas compounds an urgent need. The proteasome, a critical enzyme complex found in all eukaryotes has three catalytic subunits, β1, β2, and β5 and has been validated as a drug target to treat trichomoniasis. With the goal of developing tools to study the Tv proteasome, we isolated the enzyme complex and identified inhibitors that preferentially inactivate either one or two of the three catalytic subunits. Using a mass spectrometry‐based peptide digestion assay, these inhibitors were used to define the substrate preferences of the β1, β2 and β5 subunits. Subsequently, three model fluorogenic substrates were designed, each specific for one of the catalytic subunits. This novel substrate profiling methodology will allow for individual subunit characterization of other proteasomes of interest. Using the new substrates, we screened a library of 284 peptide epoxyketone inhibitors against Tv and determined the subunits targeted by the most active compounds. The data show that inhibition of the Tv β5 subunit alone is toxic to the parasite. Taken together, the optimized proteasome subunit substrates will be instrumental for understanding the molecular determinants of proteasome specificity and for accelerating drug development against trichomoniasis. [ABSTRACT FROM AUTHOR]

A study was conducted to analyze oligonucleotide cleavage using palladium-labile solid-phase synthesis supports. n-BuNH2/HCO2H was utilized as a reaction buffer to generate undamaged oligonucleotides. Spectrometers were also used in the study to determin 13C and 31P nuclear magnetic resonance spectra. Results suggested that an insertion mechanism by Pd(O) into the carbon-oxygen bond of the beta-cyanoethyl group influences oligonucleotide cleavage.

An expanded approach for the convergent synthesis of oligonucleotide conjugates using fully protected oligonucleotides containing alkylamine substituents at their 3'-termini is described. Redox condensation conditions resulted to high yields of bioconjugates with respect to the amount of reagents used. Moreover, variation in the nature of the peptidyl electrophile of 3'-alkylamine-containing protected oligonucleotide produced oligonucleotide-peptide conjugates of either polarity of the peptide linkage.

The preparation 4,4-disubstituted cyclohexane [beta]-keto esters from arylacetonitriles and arylacetates is described. The synthesis involved one-pot double Michael addition-Dieckmann condensation promoted by potassium tert-butoxide.

Research is presented demonstrating the use of van der Waals and hydrophobic interactions to create an orthogonal base pair for replication and storage of genetic information.

An approach for on-column derivatization of protected oligodeoxynucleotides was applied in the convergent synthesis of 5',3'-bis-conjugates. The method did not necessitate any preliminary modification of the electrophile. It involved coupling of the controlled pore glass-bound oligodeoxynucleotide using (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate and diisopropylethylamine in dimethyl fluoride. It also enabled the release of 3'-(alkylamino)oligodeoxynucleotides into solution, while retaining protecting substituents.

An orthogonal, convergent approach is described for the formation of oligonucleotide conjugates which lead to high isolated yields of homogeneous products under rapid and mild reaction conditions. Solution phase amide bond formation using protected oligonucleotides containing 3'-alkyl amines was involved in this approach. It was concluded that an efficient high-yielding solution phase method for the synthesis of protected oligonucleotide conjugates was developed.

The design, synthesis and characterization of the phosphoramidites and triphosphates of seven hydrophobic nucleobases is reported.

A practical synthesis of a potent, selective, and orally efficacious diacylglycerol acyltransferase-1 (DGAT-1) inhibitor, is described. This synthesis is suitable for multi-kilogram scale with high regioselectivity and stereoselectivity. The synthesis involves a Knoevenagel condensation with Meldrum's acid followed by the stereoselective addition of phenyl cuprate, regioselective Friedel- Crafts acylation, cyclization, and a regioselective reduction through an enol triflate with catalytic platinum oxide to provide the desired compound in 5.2% yield over 12 steps. [ABSTRACT FROM AUTHOR]

The protozoan parasite Trichomonas vaginalis (Tv) causes trichomoniasis, the most common non-viral sexually transmitted infection in the world. Although Tv has been linked to significant health complications, only two closely related 5-nitroimidazole drugs are approved for its treatment. The emergence of resistance to these drugs and lack of alternative treatment options poses an increasing threat to public health, making development of novel anti-Trichomonas compounds an urgent need. The proteasome, a critical enzyme complex found in all eukaryotes has three catalytic subunits, β1, β2, and β5 and has been validated as a drug target to treat trichomoniasis. With the goal of developing tools to study the Tv proteasome, we isolated the enzyme complex and identified inhibitors that preferentially inactivate either one or two of the three catalytic subunits. Using a mass spectrometry-based peptide digestion assay, these inhibitors were used to define the substrate preferences of the β1, β2 and β5 subunits. Subsequently, three model fluorogenic substrates were designed, each specific for one of the catalytic subunits. This novel substrate profiling methodology will allow for individual subunit characterization of other proteasomes of interest. Using the new substrates, we screened a library of 284 peptide epoxyketone inhibitors against Tv and determined the subunits targeted by the most active compounds. The data show that inhibition of the Tv β5 subunit alone is toxic to the parasite. Taken together, the optimized proteasome subunit substrates will be instrumental for understanding the molecular determinants of proteasome specificity and for accelerating drug development against trichomoniasis., (© 2024 The Protein Society.)

Selective immunoproteasome inhibition is a promising approach for treating autoimmune disorders, but optimal proteolytic active site subunit inhibition profiles remain unknown. We reveal here our design of peptide epoxyketone-based selective low molecular mass polypeptide-7 (LMP7) and multicatalytic endopeptidase complex subunit-1 (MECL-1) subunit inhibitors. Utilizing these and our previously disclosed low molecular mass polypeptide-2 (LMP2) inhibitor, we demonstrate a requirement of dual LMP7/LMP2 or LMP7/MECL-1 subunit inhibition profiles for potent cytokine expression inhibition and in vivo efficacy in an inflammatory disease model. These and additional findings toward optimized solubility led the design and selection of KZR-616 disclosed here and presently in clinical trials for treatment of rheumatic disease.