ABSTRACT
The NS3 serine protease enzyme of the hepatitis C virus (HCV) is essential for viral replication. Short peptides mimicking the N-terminal substrate cleavage products of the NS3 protease are known to act as weak inhibitors of the enzyme and have been used as templates for the design of peptidomimetic inhibitors. Automated solid-phase synthesis of a small library of compounds based on such a peptidomimetic scaffold has led to the identification of potent and highly selective inhibitors of the NS3 protease enzyme.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Viral Nonstructural Proteins/antagonists & inhibitors , Combinatorial Chemistry Techniques , Enzyme Inhibitors/pharmacology , Humans , Molecular Mimicry , Oligopeptides/chemical synthesis , Oligopeptides/pharmacology , Peptide Library , Structure-Activity RelationshipABSTRACT
Aromatic peptide nucleic acid (APNA) monomers containing N-(2-aminobenzyl)-glycine, N-(2-aminobenzyl)-(R)- or -(S)-alanine, and N-(2-aminobenzyl)-beta-alanine moieties as part of their backbone were synthesized. These novel analogues were incorporated as a single "point mutation" in PNA hexamers, and their physicochemical properties were investigated by UV thermal denaturation and CD experiments. Destabilization in triplex formation between the PNA-APNA chimeras and complementary DNA or RNA oligomers was observed, as compared to the PNA control. The APNA monomer composed of the N-(2-aminobenzyl)-glycine backbone led to the smallest decrease in the thermal stability of the triplexes formed with DNA and RNA, while maintaining selectivity for base-pairing recognition. Since the PNA-APNA chimeras are more lipophilic than the corresponding PNA homopolymers, these oligomers may also exhibit better cell membrane permeability properties.
Subject(s)
Nucleic Acid Hybridization , Peptide Nucleic Acids/chemical synthesis , Polynucleotides/metabolism , Aminobutyrates/chemical synthesis , Aminobutyrates/chemistry , Aminobutyrates/metabolism , Benzylamines/chemical synthesis , Benzylamines/chemistry , Benzylamines/metabolism , Drug Stability , Hot Temperature , Nucleic Acid Denaturation , Peptide Nucleic Acids/chemistry , Peptide Nucleic Acids/metabolism , Poly A/metabolism , ThymineABSTRACT
Two antifungal compounds isolated from the liquid culture medium of Pisolithus arhizus were identified as p-hydroxybenzoylformic acid and (R)-(-)-p-hydroxymandelic acid and given the trivial names pisolithin A and pisolithin B, respectively. The efficacy of the compounds to inhibit the germination of conidia of Truncatella hartigii was compared with that of commercially available structural analogues, and a comparable range of effectiveness for 50% germination inhibition (GI50) of conidia was recorded. The commercially available synthetic compounds (R)-mandelic acid, benzoylformic acid, and racemic p-hydroxymandelic acid, had GI50 values of 82, 72, and 59 micrograms/mL, respectively, as compared with the natural compounds pisolithin A, 67 micrograms/mL, and pisolithin B, 71 micrograms/mL. Two synthetic S enantiomers of mandelic acid, (S)-mandelic acid and (S)-(+)-p-hydroxymandelic acid, were the most effective compounds, with GI50 values of 31 and 33 micrograms/mL, respectively. A sodium salt of mandelic acid had no activity below 500 micrograms/mL. Pisolithin A and pisolithin B were compared with polyoxin D for inhibition of hyphal growth, as measured by protein estimation. Both pisolithin A and B measured higher levels of putative extractable protein than polyoxin D, but less mycelial wet weight was measured. It is suggested that the pisolithins caused a disruption of cell turgor. A measurement of mycelial dry weights of phytopathogens, incubated with the commercially available analogues, benzoylformic acid and racemic p-hydroxymandelic acid, indicated that benzoylformic acid was either more effective than, or as effective as, racemic p-hydroxymandelic acid or nystatin in arresting fungal growth.(ABSTRACT TRUNCATED AT 250 WORDS)
