Dresden 2020 – scientific programme

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O: Fachverband Oberflächenphysik

O 52: Poster Session - New Methods: Experiments

O 52.9: Poster

Tuesday, March 17, 2020, 18:15–20:00, P2/1OG

Extracting Protein Collision Cross Sections (CCSs) from Pre-Fourier Transform Mass Spectrum Transients — •Dhiren De Silva, Paul Fremdling, Tim Esser, Joseph Gault, and Stephan Rauschenbach — Department of Chemistry, Oxford University, UK

The collision cross section (CCS) of a molecule gives a sense of its size and shape and is defined as the area of a circle with radius equal to the sum of the radii of two colliding molecules. Protein CCSs have conventionally been measured through Ion Mobility experiments with dedicated instruments. More recently, procedures involving analysis of mass spectrum transients have been used to determine protein CCSs. These new methods make use of the fact that the transient signal, which is an oscillating signal due to the motion of ions in the trap, displays beating due to the superposition of the individual signals and decays in amplitude over time mainly due to ion-neutral collisions. Transients of several model proteins such as ubiquitin, cytochrome C and myoglobin in various charge states were recorded with the QE UHMR Orbitrap Mass Spectrometer. An algorithm was developed to extract the decay lifetime and calculate the CCS using ubiquitin in charge state 9 as a calibrant. We explore monitoring the CCS during native protein deposition ES-IBD experiments in a modified QE Orbitrap Mass Spectrometer. This will allow online monitoring of shape during protein deposition for imaging applications.