Untitled

Abstract

The application of adiabatic polarization-transfer experiments to resonance assignment in solid, uniformly 13C-15N-labelled polypeptides is demonstrated for the cyclic decapeptide antamanide. A homonuclear correlation experiment employing the DREAM sequence for adiabatic dipolar transfer yields a complete assignment of the C(alpha) and aliphatic side-chain 13C resonances to amino acid types. The same information can be obtained from a TOBSY experiment using the recently introduced P9(12)1 TOBSY sequence, which employs the J couplings as a transfer mechanism. A comparison of the two methods is presented. Except for some aromatic phenylalanine resonances, a complete sequence-specific assignment of the 13C and 15N resonances in antamanide is achieved by a series of selective or broadband adiabatic triple-resonance experiments. Heteronuclear transfer by adiabatic-passage Hartmann-Hahn cross polarization is combined with adiabatic homonuclear transfer by the DREAM and rotational-resonance tickling sequences into two- and three-dimensional experiments. The performance of these experiments is evaluated quantitatively.

13C, 15N Resonance Assignment of Parts of the HET-s Prion Protein in its Amyloid Form

“…Broad-band homonuclear polarization transfer used the DREAM scheme (Verel et al, 1998), (Verel et al, 2001). Narrow-band homonuclear polarization transfer employed the rotational-resonance tickling (R 2 T) method (Takegoshi et al, 1995), (Takegoshi et al, 1997), (Costa et al, 1997), (Detken et al, 2001). Sign-discrimination in the indirect dimensions was accomplished using TPPI (Marion and Wuthrich, 1983).…”

“…Several strategies for the 15 N and 13 C assignment of peptides and proteins using solidstate NMR techniques have been developed in the last few years (Petkova et al, 2003), (Detken et al, 2001), (Rienstra et al, 2000), (Ishii and Tycko, 2000), (Hong, 1999), (Straus et al, 1998). For the identification of the 13 C resonances within a residue, broadband recoupling methods are usually applied (Bennett et al, 1992), , (Carravetta et al, 2000), (Verel et al, 1998), (Verel et al, 2001), .…”

De novo determination of peptide structure with solid-state magic-angle spinning NMR spectroscopy

“…Several multidimensional chemical shift correlation methods for resolving and assigning peptide 13 C and 15 N resonances have been developed (22,25,26). Experiments for 13 C-13 C assignments generally employ either a homonuclear zero-quantum recoupling sequence such as RFDR (27) or a double-quantum sequence (28-30) such as SPC-5 (31).…”

Molecular conformation of a peptide fragment of transthyretin in an amyloid fibril

“…13 C and 15 N linewidth measurements indicate that the peptide forms highly ordered fibrils in which there is a single unique environment for each residue. We have established the complete sequence-specific backbone and side-chain 13 (8,(23)(24)(25)(26)(27), and the complete resonance assignments represent the initial step in the determination of a highresolution NMR structure for TTR(105-115) fibrils. The 15 N, 13 CO, 13 C ␣ , and 13 C ␤ chemical shifts have been used to predict the backbone torsion angles and .…”