Multi-dimensional NMR without coherence transfer: Minimizing losses in large systems.

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Multi-dimensional NMR without coherence transfer: Minimizing losses in large systems.

Multi-dimensional NMR without coherence transfer: Minimizing losses in large systems.

J Magn Reson. 2011 Jul 21;

Authors: Liu Y, Prestegard JH

Most multi-dimensional solution NMR experiments connect one dimension to another using coherence transfer steps that involve evolution under scalar couplings. While experiments of this type have been a boon to biomolecular NMR the need to work on ever larger systems pushes the limits of these procedures. Spin relaxation during transfer periods for even the most efficient (15)N-(1)H HSQC experiments can result in more than an order of magnitude loss in sensitivity for molecules in the 100kDa range. A relatively unexploited approach to preventing signal loss is to avoid coherence transfer steps entirely. Here we describe a scheme for multi-dimensional NMR spectroscopy that relies on direct frequency encoding of a second dimension by multi-frequency decoupling during acquisition, a technique that we call MD-DIRECT. A substantial improvement in sensitivity of (15)N-(1)H correlation spectra is illustrated with application to the 21kDa ADP ribosylation factor (ARF) labeled with (15)N in all alanine residues. Operation at 4°C mimics observation of a 50kDa protein at 35°C.

PMID: 21835658 [PubMed - as supplied by publisher]



Source: PubMed