Proton assisted recoupling and protein structure determination.

ABSTRACT: We introduce a homonuclear version of third spin assisted recoupling, a second-order mechanism that can be used for polarization transfer between (13)C or (15)N spins in magic angle spinning (MAS) NMR experiments, particularly at high spinning frequencies employed in contemporary high field MAS experiments. The resulting sequence, which we refer to as proton assisted recoupling (PAR), relies on a cross-term between (1)H-(13)C (or (1)H-(15)N) couplings to mediate zero quantum (13)C-(13)C (or (15)N-(15)N recoupling). In particular, using average Hamiltonian theory we derive an effective Hamiltonian for PAR and show that the transfer is mediated by trilinear terms of the form C(1) (+/-)C(2) (-/+)H(Z) for (13)C-(13)C recoupling experiments (or N(1) (+/-)N(2) (-/+)H(Z) for (15)N-(15)N). We use

SUBMITTER: De Paepe G 

PROVIDER: S-EPMC2755343 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature