Structural basis for FN3K-mediated protein deglycation.

Protein glycation is a universal, non-enzymatic modification that occurs when a sugar covalently attaches to a primary amine. These spontaneous modifications may have deleterious or regulatory effects on protein function, and their removal is mediated by the conserved metabolic kinase fructosamine-3-kinase (FN3K). Despite its crucial role in protein repair, we currently have a poor understanding of how FN3K engages or phosphorylates its substrates. By integrating structural biology and biochemistry, we elucidated the catalytic mechanism for FN3K-mediated protein deglycation. Our work identifies key amino acids required for binding and phosphorylating glycated substrates and reveals the molecular basis of an evolutionarily conserved protein repair pathway. Additional structural-functional studies revealed unique structural features of human FN3K as well as differences in the dimerization behavior and regulation of FN3K family members. Our findings improve our understanding of the structure of FN3K and its catalytic mechanism, which opens new avenues for therapeutically targeting FN3K.

Tuaimenals B-H, Merosesquiterpenes from the Irish Deep-Sea Soft Coral Duva florida with Bioactivity against Cervical Cancer Cell Lines.

Previous chemical investigation of the Irish deep-sea soft coral Duva florida led to the identification of tuaimenal A (10), a new merosesquiterpene containing a highly substituted chromene core and modest cytotoxicity against cervical cancer. Further MS/MS and NMR-guided investigation of this octocoral has resulted in the isolation and characterization of seven additional tuaimenal analogs, B-H (1-7), as well as two known A-ring aromatized steroids (8, 9), and additional tuaimenal A (10). Tuaimenals B, F, and G (1, 5, 6), bearing an oxygen at the C5 position, as well as monocyclic tuaimenal H (7), show increased cervical cancer inhibition profiles in comparison to that of 10. Tuaimenal G further displayed potent, selective cytotoxicity with an EC50 value of 0.04 µM against the C33A cell line compared to the CaSki cell line (EC50 20 µM). These data reveal the anticancer properties of tuaimenal analogs and suggest unique antiproliferation mechanisms across these secondary metabolites.