Simplified lipid II-binding antimicrobial peptides: Design, synthesis and antimicrobial activity of bioconjugates of nisin rings A and B with pore-forming peptides.

New designs of antimicrobial peptides are urgently needed in order to combat the threat posed by the recent increase of resistance to antibiotics. In this paper, we present a new series of antimicrobial peptides, based on the key structural features of the lantibiotic nisin. We have simplified the structure of nisin by conjugating the lipid II-binding motif at the N-terminus of nisin to a series of cationic peptides and peptoids with known antibacterial action and pore-forming properties. Hybrid peptides, where a hydrophilic PEG4 linker was used, showed good antibacterial activity against Micrococcus luteus.

α-Amino Aldehydes as Readily Available Chiral Aldehydes for Rh-Catalyzed Alkyne Hydroacylation.

Readily available α-amino aldehydes, incorporating a methylthiomethyl (MTM) protecting group on nitrogen, are shown to be efficient substrates in Rh-catalyzed alkyne hydroacylation reactions. The reactions are performed under mild conditions, employing a small-bite-angle bis-phosphine ligand, allowing for good functional group tolerance with high stereospecificity. Amino aldehydes derived from glycine, alanine, valine, leucine, phenylalanine, isoleucine, serine, tryptophan, methionine, and cysteine were successfully employed, as was an enantiomerically enriched α-OMTM-aldehyde derived from phenyllactic acid. The synthetic utility of the α-amino enone products is demonstrated in a short enantioselective synthesis of the natural product sphingosine.

Biased and unbiased strategies to identify biologically active small molecules.

Small molecules are central players in chemical biology studies. They promote the perturbation of cellular processes underlying diseases and enable the identification of biological targets that can be validated for therapeutic intervention. Small molecules have been shown to accurately tune a single function of pluripotent proteins in a reversible manner with exceptional temporal resolution. The identification of molecular probes and drugs remains a worthy challenge that can be addressed by the use of biased and unbiased strategies. Hypothesis-driven methodologies employs a known biological target to synthesize complementary hits while discovery-driven strategies offer the additional means of identifying previously unanticipated biological targets. This review article provides a general overview of recent synthetic frameworks that gave rise to an impressive arsenal of biologically active small molecules with unprecedented cellular mechanisms.