3
A P P L I C A T I O N N O T E
The Prometheus Panta is an instrument that
utilizes label-free methods to simultaneously
monitor the conformational and colloidal
stability characteristics of proteins along a
thermal denaturation gradient. This instrument
uses very little material, requiring only 10 µL per
sample (≥100µg /ml concentrated).
This small volume especially allows screening of
different copolymers alongside many different
membrane proteins using miniaturized expres-
sion and purification protocols.
Isothermal DLS analysis provides information
on the size (hydrodynamic radius, r
H
) and the
polydispersity index (PDI) of the membrane
proteins stabilized in the nanodiscs, allowing
the triage of copolymer nanodiscs with aberrant
sizes. Next, nanoDSF, backreflection, and DLS
data was collected along a temperature ramp
on the same 10 µL samples to review the
thermal stability of the candidates. Parameters
such as melting temperature of the protein (T
m
),
the onsets of aggregation (T
onset
Turbidity) and
sizing increase (T
onset
r
H
) confirm the folding of
the protein as well as the thermal stability of the
nanodiscs.
