Modified Ion Source for the Improved Collisional Activation of Protein Complexes

Abstract

The analysis of large molecules is challenging, as they often have salts and adducts retained through the electrospray process, which increase the observed mass and compromise the achievable mass resolution. Mild collisional activation has been shown to be very effective for the removal of adducts and increases both measurement accuracy and mass resolution of large (>100 kDa) protein complexes. Collisionally activated protein ions are more completely desolvated due to the increased number of collisions when trapped following activation. A short square quadrupole maintained at 300 mTorr by a mechanical pump was added between the ion funnel and transmission quadrupole. This configuration and operation effectively removed adducts from the 800 kDa tetradecamer GroEL as well as fragmented smaller protein complexes like C-reactive protein. Due to the gas high pressure, ions of low size-to-charge ratio, such as those in charge reducing buffers, had low ejection efficiency. We show that segmenting the quadrupole rods greatly improves signal intensity for charge reduced GroEL D398A mutant compared to nonsegmented rods when operating at high pressure.

A Simple and Flexible Infusion Platform for Automated Native Mass Spectrometry Analysis

“…Native mass spectrometry (MS) is a valuable analytical technique that enables the direct detection of noncovalent interactions in the gas phase, with applications spanning detection of distinct proteoforms, ligand binding, and protein–protein interactions . However, the typical native MS workflow is time-consuming, requiring manual sample cleanup and infusion of samples onto the mass spectrometer (see these references published in the past year − ). Implementation of more automated systems to increase throughput have been developed to eliminate the requirement of manual injection by coupling with autosampler or NanoMate devices.…”

A Simple and Flexible Infusion Platform for Automated Native Mass Spectrometry Analysis

“…Native mass spectrometry (MS) is a valuable analytical technique that enables the direct detection of noncovalent interactions in the gas phase, with applications spanning detection of distinct proteoforms, ligand binding, and protein-protein interactions 1 . However, the typical native MS workflow is time consuming, requiring manual sample clean-up and infusion of samples onto the mass spectrometer (see these references published in the past year [2][3][4][5][6] ). Implementation of more automated systems to increase throughput have been developed to eliminate the requirement of manual injection by coupling with autosampler 7 or NanoMate 8 devices.…”