MS Characterization of Serpin and its Complex Structures

摘要

In the past two decades, two structural mass spectrometry methodologies, hydroxyl radical mediated footprinting and hydrogen/deuterium (H/D) mass spectrometry, have been successfully and widely used for probing protein structure and dynamics by determining the solvent accessibility of side chains or stability and solvent accessibility of the protein backbone. In this work, the structure and dynamic properties of a metastable form of human (alpha)_(1)-antitrypsin ((alpha)_(1)AT), the most abundant serpin in human plasma, was examined by both methods. Serpins are a large family of serine and cysteine protease inhibitors. Their importance is well documented in several human diseases. The purpose of this paper is to enable the investigators to better understand the complementarity of synchrotron footprinting and H/D exchange MS methods and assist them to efficiently employ these two methods into their studies. To the best of our knowledge, this is the first report to compare synchrotron footprinting with H/D exchange MS data on the same protein. The data from the two MS methods together with molecular dynamics simulations (MD) highlight differences between the static crystal structure and the dynamic conformation of (alpha)_(1)AT in solution.