Journal: bioRxiv

Article Title: Active destabilization of the integron synaptic complex reduces bacterial adaptation to antibiotics

doi: 10.64898/2026.03.10.710562

Figure Lengend Snippet: A. Integron scheme with excision and integration shuffling pathways. B . Synaptic complex formation scheme with C-terminal tail loop-like stabilizing docking interaction. Orange IntI represent active integrase subunits, blue IntI, inactive subunits. C. Binding pocket and C-terminal α-helix tail interaction of the IntI1 synaptic complex structure predicted by AlphaFold3, zoom-in windows: polar interactions < 3.5 Å; hydrophobic interactions < 4 Å. Visualized with PyMOL (Schrödinger, L., & DeLano, W. 2020). D. C-terminal tail sequence alignment across integron integrase classes. Conserved residues are indicated in grey rectangles. Indicated residues: red for polar interactions; orange for hydrophobic contact to the pocket. Sequences were aligned using Clustal Omega Multiple Sequence Alignment (MSA) .

Article Snippet: We further generated a truncated integrase variant IntI1 ΔC plasmid using a Q5 site-directed mutagenesis kit (New England Biolabs, USA) on the p15A-integron by substituting Ala 321 and Gly 322 to stop codons (primer sequences in Table S3).

Techniques: Binding Assay, Sequencing

Journal: bioRxiv

Article Title: Active destabilization of the integron synaptic complex reduces bacterial adaptation to antibiotics

doi: 10.64898/2026.03.10.710562

Figure Lengend Snippet: A. Active synaptic complex destabilization concept: addition of a small peptide prevents C-terminal tail loop-like interaction. B. Force spectroscopy stability assay using optical tweezers; synaptic complex disassembly force indicates mechanical stability. C. Characteristic synaptic complex disassembly forces F diss as a measure of mechanical stability for the reference synaptic complex IntI1- attCaadA7 bs (“ref”) and in the presence of different peptides (N - number of measured disassembly events; concentration of pL, pS’ and pS’’ was 10 µM). pS peptide was measured at increasing concentrations (2 µM, 5 µM, 10 µM and 50 µM) as indicated by the color gradient ramp. D. Cross-class destabilization activity of mimicking peptides from IntI4 C-terminal α-helix (pS4) on IntI1- attCaadA7 bs (“ref”) synaptic complex and of mimicking peptides from IntI1 C-terminal α-helix (pS) on IntI4- attCaadA7 bs (“ref*”) synaptic complex. Concentration of pS4 and pS was 10 µM.

Article Snippet: We further generated a truncated integrase variant IntI1 ΔC plasmid using a Q5 site-directed mutagenesis kit (New England Biolabs, USA) on the p15A-integron by substituting Ala 321 and Gly 322 to stop codons (primer sequences in Table S3).

Techniques: Force Spectroscopy, Stability Assay, Concentration Assay, Activity Assay