Journal: Communications Biology

Article Title: Matching amino acids membrane preference profile to improve activity of antimicrobial peptides

doi: 10.1038/s42003-022-04164-4

Figure Lengend Snippet: a Isothermal titration calorimetry measurements of peptide interactions with DMPC:DMPG liposomes. ΔH indicates the enthalpy change. ΔS indicates the entropy change. The binding constant (or the association constant K, M–1) is the inverse of the dissociation constant (Kd). The larger binding constants of LWCopW29 and WCopW29 indicate these peptides have high affinity for the artificial bacterial membrane liposomes. An independent experiment yielded the same results (Supplementary Fig. ). b Addition of DMPC:DMPG liposomes changed the tryptophan fluorescence intensity of the peptides. In the graphs, the 340 nm maxima intensity values were normalized to the initial fluorescence value to allow comparisons of fluorescence intensities. A quencher (water or acrylamide) decreased the fluorescence intensity, while environmental hydrophobicity (lipid) increased the fluorescence intensity. Lipid concentrations are as follows: light blue, 10 μM; blue, 50 μM; dark blue, 100 μM; black, 1000 μM. The red dotted line indicates 10 μM acrylamide; the pink dotted line, 100 μM acrylamide. A high lipid concentration (1000 μM) quenched HLWCopW29-2 and HLWCopW29-4 fluorescence. This effect was comparable to that of acrylamide, indicting larger exposure of tryptophan to water. Independent experiments yielded the same results (Supplementary Fig. ). c Proton-leakage increases DiSC3(5) fluorescence in S. aureus . Peptides were added at 120 s. The fluorescence intensities of the four analogs were similar at the HLWCopW29-2 and HLWCopW29-4 MIC against OD 0.1 S. aureus (10 μM peptide each). The fluorescence intensities of LWCopW29 and WCopW29 were higher at the LWCopW29 and WCopW29 MICs (2 μM and 1 μM, respectively) (Supplementary Table ). An independent experiment yielded the same results (Supplementary Fig. ).

Article Snippet: Suspensions of bacteria and DiSC3(5) solution (90 μl) were transferred into black, clear-bottomed 96-well plates (Costar, New York, USA).

Techniques: Isothermal Titration Calorimetry, Binding Assay, Fluorescence, Concentration Assay

Journal: Advanced Science

Article Title: Precise Construction of an Antimicrobial Peptide Targeting Bacterial Cell Membranes Derived From Natural Peptides

doi: 10.1002/advs.202517068

Figure Lengend Snippet: The antibacterial mechanism of P 3‐3R‐8I . (A,B) The representative confocal fluorescence images of MRSA or E. coli (ATCC 25922) treated with P 3‐3R‐8I for different time. n = 3. Scale bar: 50 µm for low multiple images. Scale bar: 10 µm for inset images. (C) The MD simulation processes of P 3‐3R‐8I ‐gram‐positive bacterial‐mimicking membranes and the number of hydrogen bonds and contact atoms between them during MD simulation processes. (D) The MD simulation processes of P 3‐3R‐8I ‐gram‐negative bacterial‐mimicking membranes and the number of hydrogen bonds and contact atoms between them during MD simulation processes. (E,F) The fluorescence of DiSC3(5) probe (5 µM) from different groups with time. n = 3. (G,H) The docking models between P 3‐3R‐8I and Staphylococcus aureus s’ DNA/ E. coli s’ DNA. (I) The representative EMSA results of Staphylococcus aureus s’ DNA/E. colis’ DNA treated without or with P 3‐3R‐8I . 1: 0, 2: 0.25×MIC, 3: 2.5×MIC, 4: 0, 5: 0.25×MIC, 6: 2.5×MIC, time 1 h. For time dependent results, the concentration of P 3‐3R‐8I is 2.5×MIC. 37°C. n = 3. (J) The representative gel electrophoresis results of MRSA or E. coli (ATCC 25922) treated with P 3‐3R‐8I for different time. 37°C. n = 3.

Article Snippet: DiSC3(5) fluorescent probe (CAS No.: 53213‐94‐8, Cat. No.: HY‐D0085), Meropenem (CAS No.: 96036‐03‐2, Cat. No.: HY‐13678) and Vancomycin (CAS No.: 1404‐90‐6, Cat. No.: HY‐B0671) were purchased from MedChemExpress.

Techniques: Fluorescence, Concentration Assay, Nucleic Acid Electrophoresis