1：Experimental Design and Method Selection:

A correlative approach was used, combining TEM for high spatial resolution and AFM-IR for chemical characterization at the nanoscale. The rationale was to overcome the limitations of individual techniques by integrating their strengths.

2：Sample Selection and Data Sources:

The sample was the C-terminal region (CTR38) of the Hfq protein, prepared as amyloid fibers. Fibers were deposited on silicon nitride (Si3N4) supports suitable for both TEM and AFM-IR.

3：List of Experimental Equipment and Materials:

Equipment included a JEOL JEM2200FS TEM, a nanoIR2-s AFM-IR microscope with a tunable IR quantum cascade laser, Si3N4 windows (SN100-A50Q33 from EM Resolutions), gold-coated AFM probes (HQ:CSC38/CR-AU from MikroMasch), and a Fourier-transform infrared microscope (Thermo Scientific Nicolet iN10). Materials included Hfq-CTR38 peptide, CaF2 windows, and plasma cleaner.

4：0). Materials included Hfq-CTR38 peptide, CaF2 windows, and plasma cleaner. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Fibers were deposited on plasma-cleaned Si3N4 supports. AFM-IR analysis was performed first to acquire topographic images and IR spectra/maps, followed by TEM imaging. Correlative measurements involved precise positioning using light microscopy and mosaic imaging in TEM.

5：Data Analysis Methods:

AFM images and IR maps were analyzed using Mountainsmap 7.3 software. IR spectra were processed with Savitzky-Golay filtering. TEM images were reconstructed using MosaicJ plugin in ImageJ.