QSim, a program for NMR simulations.

We present QSim, a program for simulation of NMR experiments. Pulse sequences are implemented and analyzed in QSim using a mouse driven interface. QSim can handle almost any modern NMR experiment, using multiple channels, shaped pulses, mixing, decoupling, phase-cycling and pulsed field gradients.

An affibody in complex with a target protein: structure and coupled folding.

Combinatorial protein engineering provides powerful means for functional selection of novel binding proteins. One class of engineered binding proteins, denoted affibodies, is based on the three-helix scaffold of the Z domain derived from staphylococcal protein A. The Z(SPA-1) affibody has been selected from a phage-displayed library as a binder to protein A.

(13)C-(1)H NMR relaxation and fluorescence anisotropy decay study of tyrosine dynamics in motilin.

Tyrosine ring dynamics of the gastrointestinal hormone motilin was studied using two independent physical methods: fluorescence polarization anisotropy decay and NMR relaxation. Motilin, a 22-residue peptide, was selectively (13)C labeled in the ring epsilon-carbons of the single tyrosine residue. To eliminate effects of differences in peptide concentration, the same motilin sample was used in both experiments.