Premium
Conformational Changes in Calcium‐Sensor Proteins under Molecular Crowding Conditions
Author(s) -
Sulmann Stefan,
Dell'Orco Daniele,
Marino Valerio,
Behnen Petra,
Koch KarlWilhelm
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201402146
Subject(s) - calmodulin , biophysics , surface plasmon resonance , chemistry , troponin c , folding (dsp implementation) , protein folding , protein structure , recoverin , melittin , calcium , biochemistry , rhodopsin , peptide , biology , nanotechnology , materials science , troponin , retinal , nanoparticle , psychology , organic chemistry , engineering , psychiatry , myocardial infarction , electrical engineering
Fundamental components of signaling pathways are switch modes in key proteins that control start, duration, and ending of diverse signal transduction events. A large group of switch proteins are Ca 2+ sensors, which undergo conformational changes in response to oscillating intracellular Ca 2+ concentrations. Here we use dynamic light scattering and a recently developed approach based on surface plasmon resonance to compare the protein dynamics of a diverse set of prototypical Ca 2+ ‐binding proteins including calmodulin, troponin C, recoverin, and guanylate cyclase‐activating protein. Surface plasmon resonance biosensor technology allows monitoring conformational changes under molecular crowding conditions, yielding for each Ca 2+ ‐sensor protein a fingerprint profile that reflects different hydrodynamic properties under changing Ca 2+ conditions and is extremely sensitive to even fine alterations induced by point mutations. We see, for example, a correlation between surface plasmon resonance, dynamic light scattering, and size‐exclusion chromatography data. Thus, changes in protein conformation correlate not only with the hydrodynamic size, but also with a rearrangement of the protein hydration shell and a change of the dielectric constant of water or of the protein–water interface. Our study provides insight into how rather small signaling proteins that have very similar three‐dimensional folding patterns differ in their Ca 2+ ‐occupied functional state under crowding conditions.