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, 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)