Peptide News Digest

#Nature-Chemical-Biology

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Nature Chemical Biology Publishes Computational Design of Antimicrobial Peptide Nanopores; KDFA2i + 9-NH2 Matches Levofloxacin in Mouse Bacterial Load Reduction

Nature Chemical Biology published in August 2026 a research paper describing computational design of antimicrobial peptide nanopores that self-assemble into pore structures selective for bacterial membranes. The lead candidate compound, designated KDFA2i + 9-NH2, was administered intraperitoneally in a mouse infection model and reduced bacterial load by approximately 2 logs — a magnitude comparable to the reference antibiotic levofloxacin at equivalent doses. The nanopore mechanism differs from the standard cationic amphipathic peptide (CAP) mechanism of most antimicrobial peptides in that KDFA2i-class molecules assemble on the bacterial membrane into discrete transmembrane pores rather than disrupting the membrane through nonspecific electrostatic interactions. The design approach uses molecular dynamics simulations combined with generative chemistry to search sequence space for compounds that both self-assemble into a specific pore geometry and select for bacterial versus mammalian membranes. The result adds to the July 2026 Nature Communications publication of the generative-AI-designed antimicrobial peptide Arcinin (which killed drug-resistant bacteria in a mouse wound model while sparing human cells), continuing the computational-design-first shift in the antimicrobial peptide field.

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EPFL Team Builds Membrane-Permeable Cyclic Peptides From Scratch, Targeting a Core Barrier to Oral and Intracellular Peptide Drugs

A study from Christian Heinis's lab, published June 1 in Nature Chemical Biology, screened a library of 15,360 random cyclic peptides for the rare ability to cross cell membranes, then refined a lead (Peptide 30, 890.6 daltons) that blocked the intracellular Keap1-Nrf2 interaction in living cells. By engineering lower charge, fewer hydrogen-bond donors, and smaller polar surface area, the approach reaches targets inside cells without starting from a known ligand, a route toward peptide drugs that can be taken orally.

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Nature Chemical Biology May 2026: TerminaTOR Genetically Encoded Peptide mTORC1 Inhibitor Reveals Nuclear mTORC1 Regulates CCAAT-Motif Gene Transcription in Cancer

A Nature Chemical Biology paper published May 2026 reported TerminaTOR, a genetically encoded peptide inhibitor of mTORC1 that can be targeted to specific subcellular locations and used to dissect mTORC1 biology in living cells. Targeted to the lysosome, TerminaTOR inhibits canonical lysosomal mTORC1 and induces autophagy — recapitulating rapamycin's pharmacology. Targeted to the nucleus, TerminaTOR specifically inhibits nuclear mTORC1 and reveals a previously uncharacterized regulatory function: nuclear mTORC1 controls transcription of CCAAT-motif-containing genes and promotes cancer cell proliferation. The work creates a tool for spatially separating canonical (cytoplasmic) and noncanonical (nuclear) mTORC1 functions and identifies nuclear mTORC1 as a potentially druggable axis distinct from the lysosomal pathway. Therapeutic implication: cancer programs targeting mTORC1 might benefit from nucleus-selective inhibitors that spare lysosomal autophagy.