Diversity in Gold Finger Structure Elucidated by Traveling-Wave Ion Mobility Mass Spectrometry.
Traveling wave ion mobility (TWIM) mass spectrometry (MS) is a powerful method for the structural and conformational analysis of proteins and peptides, enabling the differentiation of isomeric peptides (or proteins) that have the same sequence but are modified at different residues. In this study, the TWIM-MS technique was used to separate isomeric AuImetallopeptide ions that were formed by ZnIIdisplacement from the parent zinc fingers (ZFs). The synthetic gold finger peptides were derived from the C-terminus of the HIV nucleocapsid p7 protein (NCp7-F2) and finger 3 of the Sp1 transcription factor (Sp1-F3). TWIM-MS enabled the acquisition of distinct product ion spectra for each isomer, clearly indicating the binding sites for the major conformers in the presence of multiple coordination possibilities. Collision cross-section measurements showed that the aurated peptide has a slightly more compact structure than the parent zinc compound NCp7-F2, which showed only one conformation.
Department of Chemistry, Virginia Commonwealth University, Richmond, VA, 23284-2006, USA.
Zhifeng
Z
Du
Department of Chemistry, Virginia Commonwealth University, Richmond, VA, 23284-2006, USA.
Raphael E F
RE
de Paiva
Department of Chemistry, Virginia Commonwealth University, Richmond, VA, 23284-2006, USA.
Kristina
K
Nelson
Department of Chemistry, Virginia Commonwealth University, Richmond, VA, 23284-2006, USA.
Nicholas P
0000-0001-7160-7182
NP
Farrell
conformers; gold fingers; mass spectrometry; protein structures; zinc fingers