Synthesis of new (-)-bestatin-based inhibitor libraries reveals a novel binding mode in the S1 pocket of the essential malaria M1 metalloaminopeptidase.

The malarial PfA-M1 metallo-aminopeptidase is considered a putative drug target. The natural product dipeptide mimetic, bestatin, is a potent inhibitor of PfA-M1. Herein we present a new, efficient, and high-yielding protocol for the synthesis of bestatin derivatives from natural and unnatural N-Boc-d-amino acids.

Synthesis and evaluation of an acyl-chain unsaturated analog of the Th2 biasing, immunostimulatory glycolipid, OCH.

An alpha-galactosyl ceramide (alpha-GalCer) 2 was synthesized and evaluated for its ability to stimulate iNKT-cell proliferation and elicit T-helper cytokines, IL-4 and IFNgamma. Compound 2 combines the acyl chain of the potent, Th2 biasing alpha-GalCer 1 with a sphingoid base of the same length as that found in OCH, which also exhibits Th2 skewing, Such complementation may enhance cytokine bias, which is thought to be important for therapeutic applications of iNKT cell stimulation. Two related alpha-GalCers, 3 and 4, with saturated acyl chains were prepared for comparison.

Apicomplexan parasites co-opt host calpains to facilitate their escape from infected cells.

Apicomplexan parasites, including Plasmodium falciparum and Toxoplasma gondii (the causative agents of malaria and toxoplasmosis, respectively), are responsible for considerable morbidity and mortality worldwide. These pathogenic protozoa replicate within an intracellular vacuole inside of infected host cells, from which they must escape to initiate a new lytic cycle. By integrating cell biological, pharmacological, and genetic approaches, we provide evidence that both Plasmodium and Toxoplasma hijack host cell calpain proteases to facilitate parasite egress.

Development of bestatin-based activity-based probes for metallo-aminopeptidases.

A novel set of activity-based probes (ABPs) for functionally profiling metallo-aminopeptidases was synthesized based on the bestatin inhibitor scaffold, the first synthesis of bestatin analogues using solid-phase techniques. These ABPs were shown to label metallo-aminopeptidases, using both a biotin and a fluorophore reporter, in an activity-dependent manner. This probe class was also shown to be amenable to 'click' chemistry labeling for possible use in live cells.