A quadrupole/time-of-flight mass spectrometry study of Trp-cage's conformation.

J Am Soc Mass Spectrom

Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.

Published: February 2007

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.

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http://dx.doi.org/10.1016/j.jasms.2006.09.001DOI Listing

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