Electrospray q tof mass spectrometer

Mass spectrometry measurements were performed with an electrospray Q-TOF mass spectrometer (Waters) equipped with the Nanomate device (Advion, Inc.). The HD_A_384 chip (5 μm I.D. nozzle chip, flow rate range 100−500 nL/min) was calibrated before use. For ESI − MS measurements, the Q-TOF instrument was operated in RF quadrupole mode with the TOF data being collected between m/z 400 and 2990. Collision energy was set to 10 eV and argon was used as the collision gas. PsKAI2 proteins (50 µM) in 50 mM ammonium acetate (pH 6.8) in presence or without (-)-GR24 (500 µM) were incubated for 10 min at room temperature before denaturation in 50% acetonitrile and 1% formic acid. The solutions were directly injected for Mass spectra acquisition or digested before LC-MS/MS analyses. Mass Lynx version 4.1 (Waters) and Peakview version 2.2 (Sciex) software were used for acquisition and data processing, respectively. Deconvolution of multiply charged ions was performed by applying the MaxEnt algorithm (Sciex). The average protein masses were annotated in the spectra and the estimated mass accuracy was ± 2 Da. External calibration was performed with NaI clusters (2 μg/μL, isopropanol/H₂O 50/50, Waters) in the acquisition m/z mass range.

Mass spectrometry measurements were performed with an electrospray Q‐TOF mass spectrometer (Waters) equipped with the Nanomate device (Advion Inc., Ithaca, NY, USA). The HD_A_384 chip (5 µm I.D. nozzle chip, flow rate range 100–500 nl min⁻¹) was calibrated before use. For ESI‐MS measurements, the Q‐TOF instrument was operated in RF quadrupole mode with the TOF data being collected between m/z 400 and 2990. Collision energy was set to 10 eV, and argon was used as collision gas. Mass spectra acquisition was performed after denaturation of CpD14 ± ligand in 50% acetonitrile and 1% formic acid using Mass Lynx 4.1 (Waters) and Peakview 2.2 (Sciex). Deconvolution of multiply‐charged ions was performed by applying the MaxEnt algorithm (Sciex). The estimated mass accuracy is ± 2 Da. External calibration was performed with NaI clusters (2 µg µl⁻¹, isopropanol : H₂O, 50 : 50; Waters) in the acquisition m/z mass range.