The spectra of the Spanish samples were measured on a Spectrum Two FT-IR spectrometer from Perkin-Elmer (Waltham, MA, USA) equipped with the UATR accessory. 1 μL of protein extract sample was pipetted onto the 1 reflexion ATR diamond cell and dried under gentle airflow for 2 minutes. The spectrometer was controlled using the Spectrum (v10.03.06) software (Perkin-Elmer) and the data was corrected using the in-built CO2/H2O correction available in it. Spectra were recorded from 450 cm -1 to 4000 cm -1 averaging 10 scans (measurement time ≈ 1 min) at a spectral resolution of 4 cm -1 . A background measurement of the clean diamond crystal was recorded averaging 10 scans.