NMR studies of biomolecules

The study of the structure and behavior of biomolecules is a key step to understanding their biological functions. The advent of 2D NMR, 20 years ago, allowed scientists to study small biomolecules in solution. Using this methodology we have studied the solution structure of a dithiophosphate oligonucleotide and of the signal peptide of the rat liver aldehyde dehydrogenase in a micellar environment. The dithiophosphate oligonucleotide exists preferentially as a hairpin in solution whereas the regular oligonucleotide exists as a duplex. The hairpin can be converted to a duplex form at higher salt concentrations. The signal peptide in a dodecylphosphocholine micelle exists as a helix-turn-helix structure, with one of the helices being much more stable than the other. It is possible to substantially increase the range of the biomolecules studied by NMR by adding a third dimension to the classical 2D experiment. We present the results of two 3D NMR experiments. A homonuclear 3D NOESY-TOCSY experiment applied to a oligonucleotide (a dodecamer) and a heteronuclear 3D NOESY-HMQC experiment applied to the protein bovine heart acid phosphatase (BHAP) which contains 157 amino acids and has been uniformly labelled with $\sp{15}$N