ACS Bio & Med Chem Au最新文献

The development of multitargeted drugs represents an innovative approach to cancer treatment, aiming to enhance drug effectiveness while minimizing side effects. Herein, we sought to elucidate the inhibitory effect of selagibenzophenone B derivatives on the survival of cancer cells and dual topoisomerase I/II enzyme activity. Results demonstrated that among the compounds, SelB-1 selectively inhibited the proliferation and migration of prostate cancer cells while exhibiting minimal effects on healthy cells. Furthermore, SelB-1 showed a dual inhibitory effect on topoisomerases. Computational analyses mirrored the results from enzyme inhibition assays, demonstrating the compound’s strong binding affinity to the catalytic sites of the topoisomerases. To our surprise, SelB-1 did not induce apoptosis in prostate cancer cells; instead, it induced autophagic gene expression and lipid peroxidation while reducing GSH levels, which might be associated with ferroptotic death mechanisms. To summarize, the findings suggest that SelB-1 possesses the potential to serve as a dual topoisomerase inhibitor and can be further developed as a promising candidate for prostate cancer treatment.

Disulfide-constrained peptides (DCPs) have gained increased attention as a drug modality due to their exceptional stability and combined advantages of large biologics and small molecules. Chemical synthesis, although widely used to produce DCPs, is associated with high cost, both economically and environmentally. To reduce the dependence on solid phase peptide synthesis and the negative environmental footprint associated with it, we present a highly versatile, low-cost, and environmentally friendly bioproduction platform to generate DCPs and their conjugates as well as chemically modified or isotope-labeled DCPs. Using the DCP against the E3 ubiquitin ligase Zinc and Ring Finger 3, MK1-3.6.10, as a model peptide, we have demonstrated the use of bacterial expression, combined with Ser ligation or transglutaminase-mediated XTEN ligation, to produce multivalent MK1-3.6.10 and MK1-3.6.10 with N-terminal functional groups. We have also developed a bioproduction method for the site-specific incorporation of unnatural amino acids into recombinant DCPs by the amber codon suppression system. Lastly, we produced ¹⁵N/¹³C-labeled MK1-3.6.10 with high yield and assessed the performance of a semiautomated resonance assignment workflow that could be used to accelerate binding studies and structural characterization of DCPs. This study provides a proof of concept to generate functionalized DCPs using bioproduction, providing a potential solution to alleviate the reliance on hazardous chemicals, reduce the cost, and expedite the timeline for DCP discovery.

The BRG-/BRM-associated factor (BAF) chromatin remodeling complex is a central actor in transcription. One mechanism by which BAF affects gene expression is via its various histone mark readers, including double plant homeodomains (DPF), located in the BAF45D subunit. DPF domains recognize lysine acetyl and acylations, including crotonylation, localized at promoters and enhancers. Despite a significant degree of conservation between DPF domains, attempts to crystallize BAF45D with a crotonylated histone 3 peptide (H3K14Cr) were unsuccessful. In addition, recent cryoEM and modeled structures failed to define the Req domain of BAF45D, which is responsible for reading lysine modifications. Thus, the precise mechanism of crotonyl group recognition and binding by BAF45D within the BAF complex remains unclear. We turned to protein footprinting mass spectrometry to map the binding interface between H3K14Cr and BAF45D. This technique is able to demarcate protein-binding interfaces by modifying surface-accessible residues and is not limited by protein size or composition. Experiments performed in the isolated DPF domain of BAF45D (BAF45D_DPF)-delineated H3K14Cr peptide binding across the PHD1 and PHD2 pockets. We observed markedly similar effects on the BAF45D subunit when assessing H3K14Cr binding in the purified full BAF complex. The ATPase motor, BRM, also displayed H3K14Cr-protected peptides in two separate domains that were subsequently evaluated in direct binding assays. These data confirm the BAF45D–crotonylamide interaction within its obligate complex and are the first to demonstrate H3K14Cr direct binding to BRM.