Description of the dataset: Data type: Experimental spectroscopic measurements (EPR and UV-vis), computer simulations and data analysis Files are with filename extensions: DSC, DTA, m, mat, ods, tif Information on origin of the data: EPR spectroscopic measurements have filename extensions DSC and DTA EPR spectroscopic simulation and analyses with filename extension m UV-vis spectroscopic measurements have filename extensions ods Processed data ready for simulation/figure preparation have filename extension mat (both for EPR and UV-vis) High-quality figures published in main text and supplementary are provided as tif files CW-EPR measurements were generated with a Bruker ELEXSYS E580 X-band spectrometer equipped either with an Oxford CF935 continuous flow cryostat and a Bruker ER4118 SPT-N1 resonator or with an Oxford ESR 900 continuous-flow cryostat and a Bruker ER 4122 SHQ resonator. Pulse EPR experiments were performed with an Oxford CF935 continuous flow cryostat and a Bruker ER4118 SPT-N1 resonator. Simulations of EPR spectra and fitting were performed with the Easyspin software (v. 6.0.0-dev.26) implemented in Matlab (MathWorks, R2020b) The datasetFiles with extension m normally recall files with extension mat which should be stored in the same working folder Files in PARACAT_WP3_20210929_01_CW folder include subfolders organised by topic: “Alternative cryoprotectants” contains: ready-to-plot / ready-to-simulate data in mat format; simulation scripts in m format. “Glycerol effects - different buffers” contains: ready-to-plot / ready-to-simulate data in mat format; simulation scripts in m format. Files in PARACAT_WP3_20210929_02_PULSE folder include pulse EPR spectroscopic measurements; original data are in DSC and DTA formats; processed data and fitting are in m format. Files in m format recall original data files, therefore they should be stored in the same working folder. Files in PARACAT_WP3_20210929_03_UV-VIS folder include UV-vis spectroscopic measurements; original and basic processed data are in ods format; ready-to-plot data are in mat format; scripts for figure preparation are in m format. Files in PARACAT_WP3_20210929_04_FIGURES folder include high-quality figures published in main text and supplementary, provided as tif files Information on: Specialized abbreviations: EPR – Electron Paramagnetic Resonance, CW – Continuous Wave EPR, Tm or T2– phase memory time, CAPS - N-cyclohexyl-3-aminopropanesulfonic acid, CHES - N-Cyclohexyl-2-aminoethanesulfonic acid Definitions of variables: magnetic field (mT - milliTesla), pH (pH units), UV-vis absorbance intensity (A.U. – arbitrary units), EPR intensity (A.U. – arbitrary units), Hahn Echo Intensity (A.U. – arbitrary units), g-values (adimensional) Units of measurements: Concentration: mM (millimolar), µM (micromolar), % v/v (percentage volume/volume) Volume: mL (milliliters), µL (microliters) Wavelength: nm (nanometers) Temperature: °C (Celsius degrees), K (Kelvin degrees) Time: ns (nanoseconds) Frequency: GHz (gigahertz) Power: mW (milliwatt)

o EPR data: DSC and DTA files can be opened on proprietary EPR softwares from Bruker or MatLab (version R2020b, used by the authors) with EasySpin toolbox (version 6.0.0-dev.26, used by the authors). The simulation scripts of EPR measurements (mat and m files) can be opened and run on MatLab (version R2020b, used by the authors) with EasySpin toolbox (version 6.0.0-dev.26, used by the authors). MatLab can be purchased/downloaded from: https://www.mathworks.com/products/matlab.html; EasySpin toolbox can be downloaded from: https://easyspin.org/ o UV-vis data: The ods files can be opened with programs like Microsoft Excel/Open Office Calc.