Date Published:JUN 15
Abstract:The 3D structure of protein ions in the gas phase is presently not obtainable from experiment in atomic detail. Here we use a theoretical approach to determine the 3D structure of ubiquitin +13 (UBQ +13) in the absence of solvent. Global minimization of the UBQ +13 force field within the recently developed DEEPSAM algorithm yields a nearly linear overall geometry. Four helical segments are found in this full atomistic structure - three of them are 3(10)-helices and one is an a-helix. The protein cross section computed for the predicted structure is in excellent accord with ion mobility experimental results of UBQ +13. This suggests that computational structure predictions together with (theoretical and experimental) cross section values can serve as a useful tool for determining the atomistic structures of charged proteins in the gas phase. (c) 2014 Elsevier B.V. All rights reserved.