Fig. 5

Micro-FTIR analysis of GFP-producing cells. A Micro-FTIR analysis of protein secondary structure modifications investigated in the 1700–1580 cm⁻¹ spectral range. Second derivative spectra were obtained by averaging at least 4 spectra for each condition. B Intensity ratio between the peak of β-sheet (1634 cm⁻¹) and that of α-helix (1658 cm⁻¹) secondary structures. C Micro-FTIR analysis of lipids modifications investigated in the 3000–2805 cm⁻¹. Second derivative spectra were obtained by averaging at least 4 spectra for each condition. D Intensity ratio between the peaks of CH₂ stretching (2922 + 2852 cm⁻¹) and those of CH₃ stretching (2960 + 2874 cm⁻¹). All experiments were performed in triplicate and the shadowed area (A, C) and error bars (B, D) refer to the standard deviation of the data (n = 12)