Download MendeleyStructure-based design of Sec61 translocon targeting prodrugs minimize off-target toxicity.
Hao, Q., Wang, L., Pan, H., Xiao, X., Dong, W., Pan, W., Sun, J., Su, W., Fang, L., Park, E., Yao, G.(2026) Cell Chem Biol 33: 823-836.e21
- PubMed: 42263680 Search on PubMed
- DOI: https://doi.org/10.1016/j.chembiol.2026.05.006
- Primary Citation Related Structures:
9YWS - PubMed Abstract:
Coibamide A (CbA) is a cyclic depsipeptide that inhibits the function of the Sec61 translocon and exhibits significant antitumor activity. However, its broad Sec61 inhibition results in non-selective cytotoxicity, limiting therapeutic applications. To elucidate the molecular mechanism of CbA-mediated Sec61 blockade and enable rational prodrug design, we determined the cryo-EM structure of human Sec61 bound to CbA at 3.1 Å resolution. The structure reveals that CbA adopts a distinctive lasso-like conformation and occupies the lateral gate of Sec61, a binding site shared with other Sec61 inhibitors, while forming a particularly more expansive set of interactions with the lateral gate. Guided by these structural insights, we conducted structure-activity relationship studies and developed prodrug strategies that modulate CbA's antitumor activity through the controlled perturbation of intramolecular and protein hydrogen bonding interactions. Together, these results establish a structure-guided strategy for prodrug design of CbA and demonstrate the general applicability of backbone-caging to enhance the tolerability of Sec61 inhibitors.
- School of Life Sciences, Fudan University, Shanghai 200438, China; Greater Bay Area Institute of Precision Medicine (Guangzhou), Guangzhou 510000, China.
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