%0 Journal Article
%A Marchese, Roberto
%A Grandori, Rita
%A Carloni, Paolo
%A Raugei, Simone
%T A Computational Model for Protein Ionization by Electrospray Based on Gas-Phase Basicity
%J Journal of the American Society for Mass Spectrometry
%V 23
%N 11
%@ 1879-1123
%C New York [u.a.]
%I Springer
%M FZJ-2015-03625
%P 1903 - 1910
%D 2012
%X Identifying the key factor(s) governing the overall protein charge is crucial for the interpretation of electrospray-ionization mass spectrometry data. Current hypotheses invoke different principles for folded and unfolded proteins. Here, first we investigate the gas-phase structure and energetics of several proteins of variable size and different folds. The conformer and protomer space of these proteins ions is explored exhaustively by hybrid Monte-Carlo/molecular dynamics calculations, allowing for zwitterionic states. From these calculations, the apparent gas-phase basicity of desolvated protein ions turns out to be the unifying trait dictating protein ionization by electrospray. Next, we develop a simple, general, adjustable-parameter-free model for the potential energy function of proteins. The model is capable to predict with remarkable accuracy the experimental charge of folded proteins and its well-known correlation with the square root of protein mass.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000309941700008
%R 10.1007/s13361-012-0449-0
%U https://juser.fz-juelich.de/record/201320