Ultrafextreme maldi tof tof instrument

His₆-Pga59 and His₆-Pga59^V32,33N integrity and purity were analysed on a Bruker UltrafeXtreme MALDI-TOF/TOF instrument. A volume of 15 μL of protein was passed through a ZipTip C4 and eluted on an MTP 384 ground steel target plate (Bruker-Daltonics, Germany) with 2 μL of 20 mg mL⁻¹ α-Cyano-4-hydroxycinnamic acid in 50% acetonitrile, 0.1% trifluoroacetic acid as matrix solution. Data were acquired using Flexcontrol software (Bruker-Daltonics, Germany) and shots were recorded in positive ion linear mode. Mass spectra were externally calibrated in the m/z range of 5–20 kDa with Protein I (Bruker-Daltonics, Germany) and analysed with the Flexanalysis software (Bruker).

Recombinant IrSPI protein purity and integrity were confirmed using a Bruker UltrafeXtreme MALDI-TOF/TOF instrument (Bruker-Daltonics, Germany). Briefly, 1 µL of protein at 0.075 mg/mL was deposited on an MTP 384 ground steel target plate with 1 μL of 2,5-dihydroxybenzoic acid (2,5-DHB) in 50% acetonitrile, 0.1% trifluoroacetic acid as matrix solution. Data were acquired using Flexcontrol software (Bruker-Daltonics, Germany) and shots were recorded in positive ion linear mode. Mass spectra were externally calibrated in the m/z range of 5–20 kDa with a protein calibration standard (Bruker-Daltonics, Germany) and analyzed with the Flexanalysis software (Bruker-Daltonics, Germany).