Biophysical approaches to membrane protein structure determination

Recently, there have been several technical advances in the use of solution and solid-state NMR spectroscopy to determine the structures of membrane p roteins. The structures of several isolated transmembrane (TM) helices and pairs of TM helices have been solved by solution NMR methods. Similarly, th e complete folds of two TM beta -barrel proteins with molecular weights of 16 and 19 kDa have been determined by solution NMR in detergent micelles. S olution NMR has also provided a first glimpse at the dynamics of an integra l membrane protein. Structures of individual TM helices have also been dete rmined by solid-state NMR. A combination of NMR with site-directed spin-lab el electron paramagnetic resonance or Fourier transform IR spectroscopy all ows one to assemble quite detailed protein structures in the membrane.