The requirement for next-generation antimalarials to be both curative and transmission-blocking necessitates the identification of previously undiscovered druggable molecular pathways. We identified a selective inhibitor of the Plasmodium falciparum protein kinase PfCLK3, which we used in combination with chemogenetics to validate PfCLK3 as a drug target acting at multiple parasite life stages. Consistent with a role for PfCLK3 in RNA splicing, inhibition resulted in the down-regulation of more than 400 essential parasite genes. Inhibition of PfCLK3 mediated rapid killing of asexual liver- and blood-stage P. falciparum and blockade of gametocyte development, thereby preventing transmission, and also showed parasiticidal activity against P. berghei and P. knowlesi. Hence, our data establish PfCLK3 as a target for drugs, with the potential to offer a cure—to be prophylactic and transmission blocking in malaria.

COVID‐19 is caused by a novel coronavirus called severe acute respiratory syndrome‐coronavirus 2 (SARS‐CoV‐2). Virus cell entry is mediated through a protein‐protein interaction (PPI) between the SARS‐CoV‐2 spike protein and angiotensin‐converting enzyme 2 (ACE2). A series of stapled peptide ACE2 peptidomimetics based on the ACE2 interaction motif were designed to bind the coronavirus S‐protein RBD and inhibit binding to the human ACE2 receptor. The peptidomimetics were assessed for antiviral activity in an array of assays including a neutralization pseudovirus assay, immunofluorescence (IF) assay and in‐vitro fluorescence polarization (FP) assay. However, none of the peptidomimetics showed activity in these assays, suggesting that an enhanced binding interface is required to outcompete ACE2 for S‐protein RBD binding and prevent virus internalization.

The protein kinase Pf CLK3 plays a critical role in the regulation of malarial parasite RNA splicing and is essential for the survival of blood stage Plasmodium falciparum . We recently validated Pf CLK3 as a drug target in malaria that offers prophylactic, transmission blocking, and curative potential. Herein, we describe the synthesis of our initial hit TCMDC-135051 (1) and efforts to establish a structure–activity relationship with a 7-azaindole-based series. A total of 14 analogues were assessed in a time-resolved fluorescence energy transfer assay against the full-length recombinant protein kinase Pf CLK3, and 11 analogues were further assessed in asexual 3D7 (chloroquine-sensitive) strains of P. falciparum parasites. SAR relating to rings A and B was established. These data together with analysis of activity against parasites collected from patients in the field suggest that TCMDC-135051 (1) is a promising lead compound for the development of new antimalarials with a novel mechanism of action targeting Pf CLK3.

Rapid increase in the emergence of resistance against existing antifungal drugs created a need to discover new structural classes of antifungal agents. In this study we describe the synthesis of a new structural class of short antifungal peptidomimetcis, their activity, and plausible mechanism of action. The results of the study show that peptides 11e and 11f are more potent than the control drug amphotericin B, with no cytotoxicity to human cancer cells and noncancerous mammalian kidney cells. The selectivity of peptides to fungus is depicted by transmission electron microscopy studies, and it revealed that 11e possibly disrupts the model membrane of the fungal pathogen.

Syntheses of Fmoc amino acids having zinc-binding groups were prepared and incorporated into substrate inhibitor H3K27 peptides using Fmoc/tBu solid-phase peptide synthesis (SPPS). Peptide 11, prepared using Fmoc-Asu(NHOtBu)-OH, is a potent inhibitor (IC50 = 390 nM) of the core NuRD corepressor complex (HDAC1–MTA1–RBBP4). The Fmoc amino acids have the potential to facilitate the rapid preparation of substrate peptidomimetic inhibitor (SPI) libraries in the search for selective HDAC inhibitors.