Deuterated backbone

Following Kirste and Ohm [ 1 ], the answer can be obtained from Small Angle Neutron Scattering with samples obtained from having deuterated backbone, mixed with their hydrogenated homologues ... 

Furthermore, if high ionization temperatures are employed (particularly in APCI), hydrogen-deuterium exchange of deuterated internal standard compounds may occur during the ionization process [50], For that reason, but also due to its typical location in the molecular backbone of an analyte (minimizing the influence on the electronegativity distribution of the scaffold), 13C atoms are considered the more reliable label for isotope dilution internal standardization compared to deuterium. 

Such hydrophilic macromonomers (DPn=7-9) were radically homopolymer-ized and copolymerized with styrene [78] using AIBN as an initiator at 60 °C in deuterated DMSO in order to follow the kinetics directly by NMR analysis. The macromonomer was found to be less reactive than styrene (rM=0.9 for the macromonomer and rs=1.3 for styrene). Polymerization led to amphiphilic graft copolymers with a polystyrene backbone and poly(vinyl alcohol) branches. The hydrophilic macromonomer was also used in emulsion polymerization and copolymerized onto seed polystyrene particles in order to incorporate it at the interface. 

New crosslinked elastomers may be formed by self-aggregation of substituted functional units able to form directed hydrogen-bonds. 1,4-PB has been randomly substituted with about 4 mol% urazole units [94], The urazole units form hydrogen-bonded supramolecular, plate-like aggregates which act as effective crosslinking zones, thus creating a thermoplastic elastomer [95, 96, 97]. The system is deuterated either in the PB backbone or in the urazole units, which allows to investigate the molecular dynamics in... 

Fig. 28. The C9pG10 step in the DNA dodecamer [d(CGCGAATTTCCCG)]2. Shown is the C9 nucleotide, with its cytosine base, furanose ring and linking phosphate group (C9pG10) which forms the phosphodiester backbone. The hydrogens in bold are the ones deuterated in the study of reference 120.

Relaxation times (7)) of carbon nuclei were also applied to the problem. The T, times of the CH backbone were of the same order, a result that implies the same correlation time for the motions of these carbons, including those of the terminal residues. T) data for the Phe4, Leu5, and Tyr1 side-chain carbons indicated that the motion of the Tyr side chain was relatively unrestricted. Similar conclusions were drawn earlier by an American group<152) and from H relaxation time data.(153) Uncertainties in determining the 3J(NH-CH ) values of the Gly residues of the enkephalins have been resolved by a study of specifically deuterated analogs, but the results were considered to provide... 

Ishikawa and co-workers (50, 51) have also reported the photodegradation of backbone disilane polymers (Scheme III). In this case, as in the previous example with pendant silyl substituents, silicon-silicon bond homolysis to produce silyl radicals was the predominant process. When irradiated in toluene, the photodegraded polymer showed a substantial -SiH band at 2150 cm in the IR spectrum. Similarly, NMR spectroscopic examination of the irradiated polymer showed evidence of silyl radical substitution into the solvent toluene. Irradiation of the polymeric disilane in deuterated methanol produced no bands due to Si-D in the IR spectrum and resulted in the incorporation of the elements of methanol into the chain ends (as revealed by NMR spectroscopy). For the phenyl-substituted polymer, the NMR evidence indicated that <5% of rearranged cyclohexadiene derivatives were formed. 

Despite its uncertain status as a membrane protein, the stmcture of Mistic from Bacillus subtilis determined in detergent micelles highlights a promising approach to solving the 3-D stmcture of multispaiming helical membrane proteins by solution-state NMR (50). Backbone and side-chain assignment was achieved by partial deuteration and full labeling of the protein. 

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