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Structures of Trp-cage Protein in Gas Phase

Quan Van Vuong
The Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee

This page shows visualizations of the structures of the Trp-cage protein in the gas phase. The structures were determined by Alexandra Patriksson, Christopher M. Adams, Frank Kjeldsen, Roman A. Zubarev, and David van der Spoel.1

The existence of zwitterionic proteins in the gas phase has always been questionable. Primarily, it is very difficult to determine structures of proteins experimentally in the gas phase. Several experiments have shown that the zwitterionic structure of a 20-residue protein (304 atoms), so-called Trp-cage, might exist in the vacuum. However, none of the experimental structure of the protein has been determined. Based on classical molecular dynamics simulations, Patriksson et al. have been proposed several potential structures (isomers) of the protein in the gas phase in comparison to the experimental one in solution phase.1 The stability of zwitterionic proteins is always one of my main research interests. Structures of the proteins in the gas phase are critical for our further study using quantum mechanic methods. However, Patriksson et al. did not publish their determined structures. In this project, I determined the structure of all isomers proposed by Patriksson et al.

Interactive Structures

Color Legend:

  • Hydrogen = WhiteSmoke
  • Carbon = Gray
  • Nitrogen = BLue
  • Oxygen = Red


1. Patriksson, A.; Adams, C. M.; Kjeldsen, F.; Zubarev, R. a; van der Spoel, D. A Direct Comparison of Protein Structure in the Gas and Solution Phase: The Trp-Cage. J. Phys. Chem. B 2007, 111 (46), 13147-13150, doi: 10.1021/jp709901t

posted: April 2018.
updated: April 2018.