Pitfalls in Sample Preparation of Metalloproteins for Low-Temperature EPR: The Example of Alkaline Myoglobin

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, T_m 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)