title: A Spin System Labeled and Highly Resolved ed-H(CCO)NH-TOCSY Experiment for the Facilitated Assignment of Proton Side Chains in Partially Deuterated Samples.
abstract: The introduction of deuterated and partially deuterated protein samples has greatly facilitated the 13C assignment of larger proteins. Here we present a new version of the HC(CO)NH-TOCSY experiment, the ed-H(CCO)NH-TOCSY experiment for partially deuterated samples, introducing a multi-quantum proton evolution period. This approach removes the main relaxation source (the dipolar coupling to the directly bound 13C spin) and leads to a significant reduction of the proton and carbon relaxation rates. Thus, the indirect proton dimension can be acquired with high resolution, combined with a phase labeling of the proton resonances according to the C-C spin system topology. This editing scheme, independent of the CHn multiplicity, allows to distinguish between proton side-chain positions occurring within a narrow chemical shift range. Therefore this new experiment facilitates the assignment of the proton chemical shifts of partially deuterated samples even of high molecular weights, as demonstrated on a 31 kDa protein.
authors.affiliation: Institut für Organische Chemie und Biochemie, TU München, Lichtenbergstrasse 4, D-85747, Garching, Germany.
authors.forename: R M
authors.initials: RM
authors.lastname: Gschwind
authors.forename: G
authors.initials: G
authors.lastname: Gemmecker
authors.forename: H
authors.initials: H
authors.lastname: Kessler