Application of HR-MAS NMR in the solid-phase synthesis of a glycopeptide using Sieber amide resin.
The solid-phase synthesis (SPS) of a structurally complex glycopeptide, using Sieber amide resin, was monitored by high resolution magic angle spinning NMR, demonstrating the further application of this technique. A synthetic peptidoglycan derivative, a precursor of a biologically active PGN, known to be involved in the cellular recognition, was prepared by SPS. The synthesis involved the preparation of an N-alloc glucosamine moiety and the synthesis of a simple amino acid sequence L-Ala-D-Glu-L-Lys-D-Ala-D-Ala. Last step consisted the coupling, on solid-phase, of the protected muramyl unit to the peptide chain. Proton spectra with good suppression of the polystyrene signals in swollen resin samples were obtained in DMF-d(7) as a solvent and by using a nonselective 1D TOCSY/DIPSI-2 scheme, thus allowing to follow the SPS without losses of compound and cleavage from the resin. The assignment of the proton spectra of the resin-bound amino acid sequence and of the bound glycopeptide was achieved through the combination of MAS COSY, TOCSY and NOESY.
Carvalho
Luísa R
LR
Corvo
Marta C
MC
Enugala
Ramu
R
Marques
M Manuel B
MM
Cabrita
Eurico J
EJ
D000577:Amides / Q000737:chemistry*; D006020:Glycopeptides / Q000138:chemical synthesis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000145:classification; D015394:Molecular Structure; D012117:Resins, Synthetic / Q000737:chemistry*
D000577:Amides; D006020:Glycopeptides; D012117:Resins, Synthetic