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Trehalose and calcium exert site‐specific effects on calmodulin conformation in amorphous solids
Author(s) -
Li Yunsong,
Williams Todd D.,
Schowen Richard L.,
Topp Elizabeth M.
Publication year - 2007
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.21362
Subject(s) - calmodulin , chemistry , hydrogen–deuterium exchange , trehalose , calcium , excipient , mass spectrometry , calcium binding protein , electrospray ionization , crystallography , biophysics , protein structure , biochemistry , chromatography , organic chemistry , biology
We have adapted hydrogen/deuterium (H/D) exchange with electrospray ionization mass spectrometry (ESI‐MS) to study protein conformation and excipient interactions in lyophilized solids. Using calmodulin (CaM, 17 kD) as a model protein, we demonstrate that trehalose and calcium exert site‐specific effects on protein conformation. The effects of calcium are observed primarily in the calcium binding loops, while those of trehalose are observed primarily in non‐terminal α‐helical regions. To our knowledge, this is the first demonstration of site‐specificity in the effects of excipients on protein structure in the solid state, and of the utility of H/D exchange with ESI‐MS to characterize proteins in amorphous solids. Biotechnol. Bioeng. 2007; 97: 1650–1653. © 2007 Wiley Periodicals, Inc.