Novel photochromic inhibitor for mitotic kinesin Eg5 which forms multiple isomerization states

Optical Control of Mitosis with a Photoswitchable Eg5 Inhibitor

Eg5 is a kinesin motor protein that is responsible for bipolar spindle formation and plays a crucial role during mitosis. Loss of Eg5 function leads to the formation of monopolar spindles, followed by mitotic arrest, and subsequent cell death. Several cell-permeable small molecules have been reported to inhibit Eg5 and some have been evaluated as anticancer agents. We now describe the design, synthesis, and biological evaluation of photoswitchable variants with five different pharmacophores. Our lead compound Azo-EMD is a cell permeable azobenzene that inhibits Eg5 more potently in its light-induced cis form. This activity decreased the velocity of Eg5 in single-molecule assays, promoted formation of monopolar spindles, and led to mitotic arrest in a light dependent way.

The Evaluation of DHPMs as Biotoxic Agents on Pathogen Bacterial Membranes

Herein, we present biological studies on 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) obtained via Biginelli reaction catalyzed by NH4Cl under solvent-free conditions. Until now, DHPMs have not been tested for biological activity against pathogenic E. coli strains. We tested 16 newly synthesized DHPMs as antimicrobial agents on model E. coli strains (K12 and R2–R4). Preliminary cellular studies using MIC and MBC tests and digestion of Fpg after modification of bacterial DNA suggest that these compounds may have greater potential as antibacterial agents than typically used antibiotics, such as ciprofloxacin (ci), bleomycin (b) and cloxacillin (cl). The described compounds are highly specific for pathogenic E. coli strains based on the model strains used and may be engaged in the future as new substitutes for commonly used antibiotics in clinical and nosocomial infections in the pandemic era.

Kolaflavanone, a biflavonoid derived from medicinal plant Garcinia, is an inhibitor of mitotic kinesin Eg5

Mitotic kinesin Eg5 remains a validated target in antimitotic therapy because of its essential role in the formation and maintenance of bipolar mitotic spindles. Although numerous Eg5 inhibitors of synthetic origin are known, only a few inhibitors derived from natural products have been reported. In our study, we focused on identifying novel Eg5 inhibitors from medicinal plants, particularly Garcinia species. Herein, we report the inhibitory effect of kolaflavanone (KLF), a Garcinia biflavonoid, on the ATPase and microtubule-gliding activities of mitotic kinesin Eg5. Additionally, we showed the interaction mechanism between Eg5 and KLF via in vitro and in silico analyses. The results revealed that KLF inhibited both the basal and microtubule-activated ATPase activities of Eg5. The inhibitory mechanism is allosteric, without a direct competition with adenosine-5'-diphosphate for the nucleotide-binding site. KLF also suppressed the microtubule gliding of Eg5 in vitro. The Eg5-KLF model obtained from molecular docking showed that the biflavonoid exists within the α2/α3/L5 (α2: Lys111-Glu116 and Ile135-Asp149, α3: Asn206-Thr226; L5: Gly117-Gly134) pocket, with a binding pose comparable to known Eg5 inhibitors. Overall, our data suggest that KLF is a novel allosteric inhibitor of mitotic kinesin Eg5.