Novel reverse-turn mimics inhibit farnesyl transferase

Synthetic turn mimetics and hairpin nucleators: Quo Vadimus?

Structural mimicry of peptides has witnessed perceptible progress in the last three decades. Reverse turn and β-hairpin units are the smallest secondary structural motifs that are some of the most scrutinized functional cores of peptides and proteins. The practice of mimicking, without altering the function of the bioactive core, ranges from conformational locking of the basic skeleton to total replacement of structural architecture using synthetic analogues. Development of heterogeneous backbones--using unnatural residues in place of natural ones--has broadened further opportunities for efficient structural rigidification. This feature article endeavours to trail the path of progress achieved hitherto and envisage the possibilities that lie ahead in the development of synthetic turn mimetics and hairpin nucleators.

Proline derived spirobarbiturates as highly effective beta-turn mimetics incorporating polar and functionalizable constraint elements

A practical and efficient synthesis of spirobarbiturates of type III is reported when NH acidity of the imide function of the hydrophilic linker element allowed the introduction of different substituents. Structural characterization, which was based on both X-ray crystallography and spectroscopic investigations, indicated type II beta-turn formation. Introduction of the molecular scaffold into solid phase peptide synthesis gave rise to spirocyclic neuropeptide analogs.

Thematic review series: lipid posttranslational modifications. Structural biology of protein farnesyltransferase and geranylgeranyltransferase type I

More than 100 proteins necessary for eukaryotic cell growth, differentiation, and morphology require posttranslational modification by the covalent attachment of an isoprenoid lipid (prenylation). Prenylated proteins include members of the Ras, Rab, and Rho families, lamins, CENPE and CENPF, and the gamma subunit of many small heterotrimeric G proteins. This modification is catalyzed by the protein prenyltransferases: protein farnesyltransferase (FTase), protein geranylgeranyltransferase type I (GGTase-I), and GGTase-II (or RabGGTase). In this review, we examine the structural biology of FTase and GGTase-I (the CaaX prenyltransferases) to establish a framework for understanding the molecular basis of substrate specificity and mechanism. These enzymes have been identified in a number of species, including mammals, fungi, plants, and protists. Prenyltransferase structures include complexes that represent the major steps along the reaction path, as well as a number of complexes with clinically relevant inhibitors. Such complexes may assist in the design of inhibitors that could lead to treatments for cancer, viral infection, and a number of deadly parasitic diseases.

Design, synthesis, and application of azabicyclo[X.Y.0]alkanone amino acids as constrained dipeptide surrogates and peptide mimics

Azabicyclo[X.Y.0]alkanone amino acids are challenging synthetic targets and useful tools for studying structure-activity relationships of native peptide ligands. They have been employed to increase potency and stability in conformationally rigid enzyme inhibitors and receptor ligands. Since last reviewed in 1997, activity in their synthesis and application has increased significantly and access is now available to a wider diversity of these peptide mimics. This review focuses on recent syntheses of these heterocyclic amino acids and their application in the investigation of biologically active peptides and peptide mimics.

Parallel liquid synthesis of N,N'-Disubstituted 3-amino azepin-2-ones as potent and specific farnesyl transferase inhibitors

A rapid structure-activity study was performed by parallel liquid synthesis on N,N'-disubstitution of 3-amino azepin-2-one to afford potent and specific farnesyl transferase inhibitors with low nM enzymatic and cellular activities. The activities of the selected compounds were validated in vivo, and compounds 41a and 44a presented significant antitumour activity.