Automated NMR determination of protein backbone dihedral angles from cross-correlated spin relaxation

摘要

The simultaneous interpretation of a suite of dipole-dipole and dipole-CSA cross-correlation rates involving the backbone nuclei (13)Calpha, (1)Halpha,(CO)-C-13, N-15 and H-1(N) can be used to resolve the ambiguities associated with each individual cross-correlation rate. The method is based on the transformation of experimental cross-correlation rates via calculated values based on standard peptide plane geometry and solid-state (CO)-C-13 CSA parameters into a dihedral angle probability surface. Triple resonance NMR experiments with improved sensitivity have been devised for the quantification of relaxation interference between (1)Halpha(i)-(13)Calpha(i)/N-15(i)-H-1(N)(i) and (1)Halpha(i-1)-(13)Calpha(i-1)/N-15(i)-H-1(N)(i) dipole-dipole mechanisms in N-15,C-13-labeled proteins. The approach is illustrated with an application to C-13,N-15-labeled ubiquitin. [References: 59]