Rapid automated determination of chemical shift anisotropy values in the carbonyl and carboxyl groups of fd-y21m bacteriophage using solid state NMR.

Determination of chemical shift anisotropy (CSA) in immobilized proteins and protein assemblies is one of several tools to determine protein dynamics on the timescales of microseconds and faster. The large CSA values of C=O groups in the rigid limit makes them in particular attractive for measurements of large amplitude motions, or their absence. In this study, we implement a 3D R-symmetry-based sequence that recouples the second spatial component of the C CSA with the corresponding isotropic C'-C cross-peaks in order to probe backbone and sidechain dynamics in an intact fd-y21m filamentous phage viral capsid.

Dynamics and Rigidity of an Intact Filamentous Bacteriophage Virus Probed by Magic Angle Spinning NMR.

The capsid dynamics of filamentous bacteriophages is related to their function, stability, and interactions with the genome, and can be assessed by measuring the chemical shift anisotropy (CSA) of N amides, which are sensitive to large amplitude motions. In this study, CSA recoupling experiments under magic-angle spinning NMR were used to probe the dynamics of the y21m capsid mutant of fd bacteriophage. Based on fitting the generated CSA lineshapes, residues located in the N-terminus undergo increased motional amplitudes suggesting its global motion, whereas other backbone residues are rigid, and imply a tight hydrophobic packing of the phage.