We developed versatile actin-affinity tags from the side-chain analogs of aplyronine A, an antitumor marine macrolide.

Cancer is one of the death causes in the world. Many plants act as anticancer, one of them is Curcuma longa. The purpose of this study was to analyze the molecular mechanism of compounds in Curcuma longa as an anticancer using in silico. These research methods included exploration of the active compounds of Curcuma longa plants, prediction of their activity, human intestinal absorption test, test of Lipinski's rule of five, molecular docking, and interactions of receptor with compounds as well as signaling pathways. The results showed that Curcuma longa had 20 compounds that have the potential as an anticancer. As many as 5 of the 20 active compounds, namely α-curcumene, curcumenol, curcumin, curcumin II, and curcumin III had a value of Pa > 0.3 and HIA above 80%. The results of molecular docking of α-curcumene, curcumenol, curcumin, curcumin II, and curcumin III compounds with protein receptors of VEGFR-2, EGFR, and FGFR-1 showed ∆Gbind values of -5.0 to -7.5 kcal/mol. The compound in Curcuma longa that had the most effective activity as an anticancer was curcumin with a ∆Gbind value of -7.5 kcal/mol at the FGFR-1 receptor. Curcumin molecular mechanism as antiproliferative was revealed computationally through inhibition of the PI3K/AKT/mTOR pathway.

The caseinolytic protease (Clp) system plays an essential role in the protein homeostasis of the malaria parasite, particularly at the stage of apicoplast development. The inhibition of this protein is known to have a lethal effect on the parasite and is therefore considered an interesting avenue for antimalaria drugs discovery. The catalytic activity of the Clp system is modulated by its proteolytic subunit (ClpP), which belongs to the serine protease family member and is therefore extensively studied for further inhibitors development. Among many inhibitors, the group of β-lactone is known to be a specific inhibitor for ClpP. Nevertheless, other groups of lactones have never been studied. This study aims to characterize the catalytic properties of ClpP of Plasmodium knowlesi (Pk-ClpP) and the inhibition properties of a δ-lactone hyptolide against this protein. Accordingly, a codon-optimized synthetic gene encoding Pk-ClpP was expressed in Escherichia coli BL21(DE3) and purified under a single step of Ni²⁺-affinity chromatography, yielding a 2.20 mg from 1 L culture. Meanwhile, size-exclusion chromatography indicated that Pk-ClpP migrated primarily as homoheptameric with a size of 205 kDa. The specific activity of pure Pk-ClpP was 0.73 U µg⁻¹, with a catalytic efficiency k_cat/K_M of 0.05 µM⁻¹ s⁻¹, with optimum temperature and pH of 50 °C and 7.0–7.5, respectively. Interestingly, hyptolide, a member of δ-lactone, was shown to inhibit Pk-ClpP with an IC₅₀ value of 17.36 ± 1.44 nM. Structural homology modelling, secondary structure prediction, and far-UV CD spectra revealed that helical structures dominate this protein. In addition, the structural homology modeling showed that this protein forms a barrel-shaped homoheptamer. Docking simulation revealed that the inhibition was found to be a competitive inhibition in which hyptolide was able to dock into the catalytic site and block the substrate. The competitiveness of hyptolide is due to the higher binding affinity of this molecule than the substrate.