BE.342/442 Tuesday, October 4th, 2005
Topic: Guest Lecture on NMR by Peter Carr (Research Scientist, MIT Media Lab)
Background of speaker: Used NMR as a tool to study complex protein dynamics. Currently
utilizes little NMR; studies molecular biology/protein engineering to build genes “from scratch”
for protein synthesis.
NMR can be look at biomolecules, as well as polymers and inorganic compounds. In biology,
used to study proteins, pieces of DNA, and other large systems. NMR can give atomic-level
resolution of these large molecules. Secondary structures (alpha helices, beta-sheets), tertiary
structures (overall fold of a protein), and quaternary structures (binding and interfaces between
multiple molecules) can be resolved as well.
NMR can be performed dynamically, from picoseconds to milliseconds (folding/unfolding of
DNA, concerted motions of entire molecules, binding of a small molecule or drug to DNA)
Solution State vs. Solid State NMR:
Samples can be liquid, including simple or complex solutions, or solids, including crystals,
colloids, or disordered powders. Sometimes, samples can even be in a gas phase!
NMR Periodic Table:
NMR can detect an isotopes of atoms. Common atoms such as hydrogen, oxygen, nitrogen, etc.
have at least one isotope that can be distinguished by NMR. Relative sensitivity is determined by
the natural abundance of the isotope multiplied by magnetic sensitivity of that isotope.
convenient of all are the spin-½ nuclei, including hydrogen, carbon, nitrogen, and phosphorus.
Carbon and nitrogen are present in every protein and nucleotide base, and are so common to use
in NMR that companies dedicate themselves to production of these isotopes! Phosphorus, in the
backbone of every oligonucleotide, provides a strong NMR signal.
The NMR Spectrometer