Ptc 423s 15 temperature

Circular dichroism (CD) spectra were recorded on a Jasco J-715 spectropolarimeter equipped with a Jasco Peltier PTC-423S/15 temperature controller (Jasco Europe S.r.l, Cremella, Italy) using a Hellma-238-QS tandem quartz cell (2 × 0.4375 cm from Hellma Italia S.r.l., Milano, Italy) according to the previous literature experiments [50 (link),51 (link),52 (link),53 (link),54 (link),55 (link),56 (link),57 (link),58 (link),59 (link)] with a response time of 1 s, a scanning speed of 100 nm min⁻¹, and a bandwidth of 2.0 nm in the 205–260 nm wavelength range. All the spectra were averaged over three scans. UV absorption spectra were collected simultaneously to CD on the same instrument [60 (link)] to minimize possible errors induced by separate measurements on different instruments [61 (link)]. CD (Δε) values (M⁻¹ cm⁻¹) were calculated according to the equation: Δε = θ/(32980 × C × l), with θ being the measured ellipticity (mdeg), C the concentration (M), and l the optical path length (cm). All experiments were performed at 10 °C in 10 mM of sodium phosphate buffer at pH 7.4. The concentration of BSA (Sigma-Aldrich) was 1.5 μM.

Circular dichroism (CD) spectra were recorded using a J-815 CD spectrometer (Jasco, Tokyo, Japan) with a PTC-423S/15 temperature controller (Jasco, Tokyo, Japan). All the measurements were conducted under nitrogen gas of 1.0 MPa. The CD spectra were measured at 22 °C with a frequency resolution of 0.2 nm. The concentrations of Mb and COMb solutions were 25 μM and 15 μM, respectively. For the Soret and Q band CD spectra measurements, a quartz cell with the pathlength of 10 mm was used. For of the temperature-controlled CD spectra of the protein backbone, the pathlength used was 0.2 mm. During the temperature-controlled data measurement, the temperature was raised by 10 °C in ~10 min, and then the sample was left at the target temperature for 10 min to equilibrate. A real temperature of the solution in the CD cell was determined with a thermocouple detector in each measurement.