The lipid and small metabolite profiles from intact muscles of Arctic char were investigated using (1)H high-resolution magic angle spinning ((1)H HR-MAS) NMR spectroscopy. Not only the total n-3 fatty acid content but also the eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) contents of the muscle were obtained from the (1)H HR-MAS NMR spectra without pretreatment of the tissue or lipophilic extraction. A number of small metabolites could also be observed, where creatine/phosphocreatine, anserine and taurine were the most abundant. Thus, the use of (1)H HR-MAS NMR led to simplified analysis techniques that can give direct information on the nutritional value of the fish.

NMR of a uniformly 13C-labeled carbohydrate was used to elucidate the atomic details of a sugar-protein complex. The structure of the 13C-labeled Manα(1–2)Manα(1–2)ManαOMe trisaccharide ligand when bound to cyanovirin-N was characterized and revealed that in the complex the glycosidic linkage torsion angles between the two reducing-end mannoses are different from the free trisaccharide. Distances within the carbohydrate were employed for conformational analysis, and NOE-based distance mapping between sugar and protein revealed that Manα(1–2)Manα(1–2)ManαOMe is bound more intimately with its two reducing-end mannoses into the domain A binding site of CV-N than with the non-reducing end unit. Taking advantage of the 13C spectral dispersion of 13C-labeled carbohydrates in isotope-filtered experiments is a versatile means for a simultaneous mapping of the binding interactions on both, the carbohydrate and the protein.

DNA-free genome editing was used to induce mutations in one or two branching enzyme genes (Sbe) in tetraploid potato to develop starch with an increased amylose ratio and elongated amylopectin chains. By using ribonucleoprotein (RNP) transfection of potato protoplasts, a mutation frequency up to 72% was achieved. The large variation of mutations was grouped as follows: Group 1 lines with all alleles of Sbe1 mutated, Group 2 lines with all alleles of Sbe1 as well as two to three alleles of Sbe2 mutated and Group 3 lines having all alleles of both genes mutated. Starch from lines in Group 3 was found to be essentially free of amylopectin with no detectable branching and a chain length (CL) distribution where not only the major amylopectin fraction but also the shortest amylose chains were lost. Surprisingly, the starch still formed granules in a low-ordered crystalline structure. Starch from lines of Group 2 had an increased CL with a higher proportion of intermediate-sized chains, an altered granule phenotype but a crystalline structure in the granules similar to wild-type starch. Minor changes in CL could also be detected for the Group 1 starches when studied at a higher resolution.

Hydroxyl proton resonances of uniformly C-labeled Manα(1-2)Manα(1-2)ManαOMe (Man) bound to cyanovirin-N (CV-N) were detected at ambient temperature in aqueous solution by NMR spectroscopy. The directions of the hydroxyl groups were determined on the basis of NOEs, and a previously unknown hydrogen-bonding network between Man and CV-N was discovered. This is the first report on detecting hydroxyl protons of a protein-bound carbohydrate in aqueous solution by NMR. Approaches such as those presented here may open the door for accurately determining intermolecular hydrogen bonds in carbohydrate-protein complexes.

Metal oxide nanoparticles are potentially attractive tools for biomedical applications such as bioimaging and drug delivery. This urges experimental studies of their surface interaction with biomolecules, in the first hand, amino acids and proteins. Especially intriguing is the effect of not only shape and size but of chemical nature of the particles on the nature of bonds emerging between them and biomolecules. In present study we isolated, structurally characterized and compared complexes with model molecules glycylglycine and arginine of spherically shaped Keggin POMs [PM 12 O 40 ] 3-, M = Mo, W as models for individual nanoparticles ca. 1 nm in size. Surpris- [a]