Novel peptide mimetic building blocks and strategies for efficient lead finding

Discovery of novel, highly potent and selective beta-hairpin mimetic CXCR4 inhibitors with excellent anti-HIV activity and pharmacokinetic profiles

Novel highly potent CXCR4 inhibitors with good pharmacokinetic properties were designed and optimized starting from the naturally occurring beta-hairpin peptide polyphemusin II. The design involved incorporating important residues from polyphemusin II into a macrocyclic template-bound beta-hairpin mimetic. Using a parallel synthesis approach, the potency and ADME properties of the mimetics were optimized in iterative cycles, resulting in the CXCR4 inhibitors POL2438 and POL3026. The inhibitory potencies of these compounds were confirmed in a series of HIV-1 invasion assays in vitro. POL3026 showed excellent plasma stability, high selectivity for CXCR4, favorable pharmacokinetic properties in the dog, and thus has the potential to become a therapeutic compound for application in the treatment of HIV infections (as an entry inhibitor), cancer (for angiogenesis suppression and inhibition of metastasis), inflammation, and in stem cell transplant therapy.

The first oligopeptide derivative of 1′-aminoferrocene-1-carboxylic acid shows helical chirality with antiparallel strands

The unnatural organometallic amino acid 1'-aminoferrocene-1-carboxylic acid (Fca) induces a turn structure in a tetrapeptide with anti-parallel strands which is stabilized by two intra-molecular hydrogen bonds in the solid state and in solution.

Stereoselective synthesis of conformationally constrained glycosylated amino acids using an enzyme-catalyzed desymmetrization

As part of an effort to probe the mechanism by which glycosyltransferases recognize glycoproteins and assemble the core structures of O-linked oligosaccharides, constrained glycopeptides, compounds 2 and 3, based on the alpha-N-acetylgalactosaminyl serine substructure 1, were designed. In this paper we describe a stereoselective preparation of protected versions of these compounds. A pig liver esterase-catalyzed enzymatic desymmetrization of a diacetate substrate, 10, was employed as a key component in the synthesis.

Solid-supported synthesis of putative peptide beta-turn mimetics via Ugi reaction for diketopiperazine formation

The scope and limitations of the solid-supported synthesis of a bicyclic diketopiperazine, an internal, putative peptide beta-turn mimetic, are presented. The 4CC multicomponent Ugi reaction of alpha-N-Boc-diaminopropionic acid resin ester (an amine input), optically active alpha-bromoacid, aldehyde, and isocyanide is the key step in the proposed synthetic protocol. Application of cyclitive cleavage as the final step led to desired products in high purity.

Crystal structure of a synthetic cyclodecapeptide for template-assembled synthetic protein design

The structural prototype of a new generation of regioselectively addressable functionalized templates (RAFTs) for use in protein de novo design has been synthesized and crystallized. The structure of the aromatically substituted cyclodecapeptide was determined by X-ray diffraction; it consists of an antiparallel beta sheet spanned by heterochirally induced type IIprime prime or minute beta turns, similar to that observed in gramicidin S. The three-dimensional structure of the artificial template was also examined by an NMR spectroscopic analysis in solution and shown to be compatible with a beta-sheet plane suitable for accommodating secondary functional peptide fragments for the synthesis of template-assembled synthetic proteins (TASPs).