1 mm quartz cuvettes

PBRM1-BD4 secondary structure was assessed using a J-1500 CD spectrophotometer (JASCO). The samples were prepared at a concentration of 0.4 mg/ml in buffer (50 mM Na₃PO₄, 200 mM NaF, 5% v/v glycerol, pH 7.5 at 20 °C) and placed in 1 mm quartz cuvettes (Thermo Fisher Scientific). CD spectra were recorded at 25 °C from 280 to 200 nm, with a data pitch of 0.1 nm. A bandwidth of 1 nm was used with a digital integration time of 1 s and a scanning speed of 50 nm/min. Each spectrum was accumulated from five scans and corrected by subtracting the buffer spectrum from the sample spectrum. The data was processed using Spectra Analysis software supplied by the manufacturer (JASCO, https://jascoinc.com/products/spectroscopy/molecular-spectroscopy-software/) and transferred to GraphPad Prism for presentation.

CD measurements (178 to 280 nm, 1-nm data pitch, continuous scanning with 1-nm bandwidth, 60 nm/min, and 5 accumulations) with ~10 μM CHMP4 paralogs in 10 mM sodium phosphate (pH 6.5) were carried out in 1-mm quartz cuvettes (Thermo Fisher Scientific, catalog no. NC9651589) using an Aviv model 215 spectrometer. CD data were analyzed as described previously (23 (link)).