Comparison of protein structures by high resolution solid state and solution NMR

Comparisons of the crystal and solution structure of proteins are usually based on circumstantial evidence. Direct structure determination is possible only in the solid state, and to make the comparison, various spectroscopic findings (CD, ORD, NMR), or results of chemical modification experiments are tested for consistency with the known crystal structure [ 11. To be rigorous a comparison should be based on data obtained by the same method on the same object under two different conditions. Here we present an experiment which makes such a direct comparison of the crystal and solution structure of proteins by high resolution “C NMR.