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Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

2018

Western University

Mass

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Full-Text Articles in Physical Sciences and Mathematics

Chain Ejection Model For Electrospray Ionization Of Unfolded Proteins: Evidence From Atomistic Simulations And Ion Mobility Spectrometry., Haidy Metwally, Quentin Duez, Lars Konermann Aug 2018

Chain Ejection Model For Electrospray Ionization Of Unfolded Proteins: Evidence From Atomistic Simulations And Ion Mobility Spectrometry., Haidy Metwally, Quentin Duez, Lars Konermann

Chemistry Publications

The ion evaporation model (IEM) and the charged residue model (CRM) represent cornerstones of any discussion related to the mechanism of electrospray ionization (ESI). Molecular dynamics (MD) simulations have confirmed that small ions such as Na+ are ejected from the surface of aqueous ESI droplets (IEM), while folded proteins in native ESI are released by water evaporation to dryness (CRM). ESI of unfolded proteins yields [M + zH] z+ ions that are much more highly charged than their folded counterparts. A chain ejection model (CEM) has been proposed to account for the protein ESI behavior under such non-native conditions …


How To Run Molecular Dynamics Simulations On Electrospray Droplets And Gas Phase Proteins: Basic Guidelines And Selected Applications., Lars Konermann, Haidy Metwally, Robert G Mcallister, Vlad Popa Jul 2018

How To Run Molecular Dynamics Simulations On Electrospray Droplets And Gas Phase Proteins: Basic Guidelines And Selected Applications., Lars Konermann, Haidy Metwally, Robert G Mcallister, Vlad Popa

Chemistry Publications

The ability to transfer intact proteins and protein complexes into the gas phase by electrospray ionization (ESI) has opened up numerous mass spectrometry (MS)-based avenues for exploring biomolecular structure and function. However, many details regarding the ESI process and the properties of gaseous analyte ions are difficult to decipher when relying solely on experimental data. Molecular dynamics (MD) simulations can provide additional insights into the behavior of ESI droplets and protein ions. This review is geared primarily towards experimentalists who wish to adopt MD simulations as a complementary research tool. We touch on basic points such as force fields, the …


Crown Ether Effects On The Location Of Charge Carriers In Electrospray Droplets: Implications For The Mechanism Of Protein Charging And Supercharging., Haidy Metwally, Lars Konermann Mar 2018

Crown Ether Effects On The Location Of Charge Carriers In Electrospray Droplets: Implications For The Mechanism Of Protein Charging And Supercharging., Haidy Metwally, Lars Konermann

Chemistry Publications

"Native" electrospray ionization (ESI) mass spectrometry (MS) aims to transfer proteins from solution into the gas phase while maintaining solution-like structures and interactions. The ability to control the charge states of protein ions produced in these experiments is of considerable importance. Supercharging agents (SCAs) such as sulfolane greatly elevate charge states without significantly affecting the protein structure in bulk aqueous solution. The origin of native ESI supercharging remains contentious. According to one model, SCAs trigger unfolding within ESI droplets. In contrast, the "charge trapping model" envisions that SCAs impede the ejection of charge carriers (e.g., NH4+ or Na …