Effective Ion Mobility Calculations for Macromolecules by Scattering off Electron Clouds
Broad commercialization and increasing resolving power of ion mobility spectrometry/mass spectrometry (IMS/MS) platforms has engendered an explosion of IMS applications to structural characterization of gas-phase biomolecules. That has renewed interest in more accurate and rapid ion mobility calculations needed to elicit ion geometries from the measurements. An approach based on scattering off electron density isosurfaces (SEDI) that mirrors the physics of molecular collisions was proven superior to the common methods involving atomic coordinates a decade ago, but has remained impractical for large ions because of extreme computational demands. Here, we accelerate SEDI by up to ~500 times using the fragment molecular orbital (FMO) approach for surface generation and the multiplexed scattering algorithm in conjunction with the new grid extrapolation procedure for cross section evaluations. Parallelization of the code on a supercomputer has produced major further speed gains, allowing SEDI calculations for proteins (defined by over a million surface points) with the precision of <0.1% in one minute. Initial tests reveal the anticipated dependences of mobility on the ion charge state and lower cross sections in view of reduced surface roughness. Present developments are expected to lead to broad application of SEDI in IMS studies of macromolecules, enabling more accurate and reliable structural assignments.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1170452
- Report Number(s):
- PNNL-SA-104419; KP1601010
- Journal Information:
- Journal of Physical Chemistry A, 118(34):6763-6772, Journal Name: Journal of Physical Chemistry A, 118(34):6763-6772
- Country of Publication:
- United States
- Language:
- English
Similar Records
AutoCCS: automated collision cross-section calculation software for ion mobility spectrometry–mass spectrometry
Modeling ionic mobilities by scattering on electronic density isosurfaces: Application to silicon cluster anions