14
3. Using the Prometheus Series Instruments
3.1.
General Usage
Start the Prometheus instrument using the power switch at the back left of the instrument, turn
on the control computer and start the software (PR.ThermControl, PR.TimeControl or
PR.ChemControl). It will take approximately one minute for the Prometheus instrument to
complete hardware initialization. You can use the touch display of the Prometheus instrument
to set the internal temperature to a desired value, and to open the capillary tray drawer. These
commands can also be performed in the control software.
After the experimental session is finished, turn the Prometheus instrument off using the switch.
Shut down the control computer. No particular sequence needs to be followed.
Note: No equilibration times are required after startup. Prior to temperature ramps, the
Prometheus instruments automatically perform a one minute equilibration routine.
Note: Always remove capillaries and capillary lids prior to transport of the instrument.
3.2.
Sample Loading
Clean the mirrored surface of the capillary tray with a scratch- and dust-free tissue and 99.8 %
ethanol prior to experiments. Keep the tray surface free from dust, dirt and scratches. In order
to detect protein unfolding, proteins must contain at least one tryptophan or other fluorescent
residues that show changes in their fluorescent properties in the dedicated detection range.
10 µl of sample are required per capillary for unfolding experiments. Capillaries (or capillary
chips) are dipped into the sample and automatically fill by capillary forces. Capillary filling is
accelerated by holding the capillary horizontally. Make sure that capillaries are filled
completely. Tolerable capillary filling levels for thermal unfolding experiments are shown in
(top right panel). Once capillaries are filled, place them onto the capillary tray and fix
the capillaries by placing the lid onto the tray. Differences in sample loading between different
Prometheus Series instruments are described in the following sections.
Note: NanoTemper Technologies offers two different types of capillaries, nanoDSF Grade
Standard Capillaries and nanoDSF Grade High Sensitivity Capillaries. To improve sensitivity
at sample concentrations < 200 µg/ml, the nanoDSF Grade High Sensitivity capillaries are
recommended.
Note: Avoid liquid on the outside of the capillary, since this will alter the fluorescence signal. If
there is liquid on the outside of the capillaries, use a dust- and scratch-free tissue to wipe the
capillaries clean.
Note: In case of broken capillaries on the capillary tray, use a paintbrush or tissue to carefully
remove pieces of glass and to avoid scratching the tray.
