Abstract
The biological environment in which a protein performs its function is a crowded milieu containing millions of molecules that can potentially lead to a great many transient, non-specific interactions. NMR spectroscopy is especially well suited to study these weak molecular contacts. Here, non-specific interactions between the Ca(2+)-bound form of calmodulin (CaM) and non-cognate proteins in Escherichia coli lysate are explored using Ile, Leu, Val and Met methyl probes. Changes in CaM methyl chemical shifts as a function of added E. coli lysate are measured to determine a minimum ’average’ dissociation constant for interactions between Ca(2+)-CaM and E. coli lysate proteins. (2)H R 2 and (13)C R 1 spin relaxation rates report on the binding reaction as well. Our results further highlight the power of methyl containing side-chains for characterizing biomolecular interactions, even in complex in-cell like environments.
Original language | English |
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Pages (from-to) | 239–47 |
Journal | Journal of Biomolecular NMR |
State | Published - Mar 2013 |