Unexpected interactions

摘要

In folded proteins, it is quite easy to find places where the distance between the hydrogen atom in a carbon-hydrogen (C-H) bond and a sulphur atom in a nearby cysteine amino-acid residue is less than 4 angstroms. But no one had suggested that this might be evidence of a weak hydrogen-bond-like interaction - until now. Reporting in the Journal of the American Chemical Society, Westler et al.1 describe unexpectedly large shifts of peaks associated with certain carbon nuclei in the nuclear magnetic resonance (NMR) spectrum of the protein rubredoxin.