Protein dynamics measurements by TROSY-based NMR experiments

The described TROSY-based experiments for investigating backbone dynamics o f proteins make it possible to elucidate internal motions in large proteins via measurements of T-1, T-2, and NOE of backbone N-15 nuclei. In our prop osed sequences, the INEPT sequence is eliminated and the PEP sequence is re placed by the STZ-PT sequence from the HSQC-based experiments. This has the benefit of shortening the pulse sequences by 5.4 ms (= 1/2J) and results i n an increase in the intrinsic sensitivity of the proposed TROSY-based expe riments. The TROSY-based experiments are on average of 13% more sensitive t han the corresponding HSQC-based experiments on a uniformly N-15-labeled Xe nopus laevis calcium-bound calmodulin sample on a 750-MHz spectrometer at 5 degrees C. The amide proton linewidths of the TROSY-based experiments are 2-13 Hz narrower than those of the HSQC experiments. More sensitivity gain and higher resolution are expected if the protein sample is deuterated. (C) 2000 Academic Press.