title: A quadrupole/time-of-flight mass spectrometry study of Trp-cage's conformation.
abstract: Trp-cage is a synthetic 20-residue miniprotein that uses tertiary contacts to stabilize its native conformation. NMR, circular dichroism (CD), and UV-resonance Raman spectroscopy were used to probe its energy landscape. In this quadrupole/time-of-flight study, electrospray ionization charge state distribution (CSD) and solution-phase H/D exchange are used to probe Trp-cage's tertiary structure. The CSDs of Trp-cage and its mutant provide spectra showing a pH-dependent conformation change. Solution-phase H/D exchange in 30% deuterated trifluoroethanol solution of the wild type shows increased protection of one labile hydrogen in the native state. Together, CSDs and solution-phase H/D exchange are demonstrated to constitute a simple but effective means to follow conformation changes in a small tertiary protein.
authors.affiliation: Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
authors.forename: Mingxiang
authors.initials: M
authors.lastname: Lin
authors.forename: Zeeshan
authors.initials: Z
authors.lastname: Ahmed
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Taormina
authors.forename: Kasi V
authors.initials: KV
authors.lastname: Somayajula
mesh_terms: D002942:Circular Dichroism; D010449:Peptide Mapping; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods*; D013059:Spectrum Analysis, Raman
chemical_list: D010455:Peptides; C508725:Trp-cage peptide