Assignment of acyl chain resonances from membranes of mammalian cells by two-dimensional NMR methods

Nuclear magnetic resonance spectroscopy (NMR) has developed into a powerful tool for study of the biochemistry of intact cells and tissue samples. While most studies have utilized 13C or 31P NMR [see Roberts & Jardetzky (1981) and Kuchel (1981) for reviews], NMR is being applied increasingly (Brindle et al., 1979; Ogino et al., 1980; Agris & Campbell, 1982; Behar et al., 1983). NMR is particularly attractive because of the much higher sensitivity of this nucleus relative to 13C or 31P. A major problem encountered in studies of cell or tissue samples is the resolution and assignment of proton resonances to particular cellular constituents. Assignments are frequently made on the basis of comparable chemical shifts in the spectra of the cells and of the isolated constituents. This is a hazardous procedure at best. Chemical shifts may be displaced for molecules within the cell or tissue as a result of interactions between cellular constituents (Daniels et al., 1976, 1978)..