Clickable analogue of cerulenin as chemical probe to explore protein palmitoylation.

Dynamic palmitoylation is an important post-translational modification regulating protein localization, trafficking, and signaling activities. The Asp-His-His-Cys (DHHC) domain containing enzymes are evolutionarily conserved palmitoyl acyltransferases (PATs) mediating diverse protein S-palmitoylation. Cerulenin is a natural product inhibitor of fatty acid biosynthesis and protein palmitoylation, through irreversible alkylation of the cysteine residues in the enzymes. Here, we report the synthesis and characterization of a "clickable" and long alkyl chain analogue of cerulenin as a chemical probe to investigate its cellular targets and to label and profile PATs in vitro and in live cells. Our results showed that the probe could stably label the DHHC-family PATs and enable mass spectrometry studies of PATs and other target proteins in the cellular proteome. Such probe provides a new chemical tool to dissect the functions of palmitoylating enzymes in cell signaling and diseases and reveals new cellular targets of the natural product cerulenin.

Syntheses of cerulenin and its analogs. II. Synthesis and biological activity of dl-carbacerulenin, a carbocyclic analog of cerulenin.

2,3-Epoxy-4-hydroxy-4-((E,E)-3,6-octadienyl)cyclopentanone (dl-carbacerulenin 5) was synthesized via the epoxyketones 15a and 15b as a mimic of the active form of the antibiotics cerulenin 1, a potent inhibitor of fatty acid synthetase (FAS). The monobenzyl ethers (12 and 13), synthetic intermediates of 15, were prepared by direct benzylation of the epoxycyclopentene (7). Inhibitory activity of synthesized 5 toward yeast FAS was less than that of cerulenin by a factor of 1000.