Chapter 5 SOLARIA: a protocol for automated cross- peak assignment and structure calculation for solid-state magic-angle spinning NMR

Recently, is has been shown that structures of proteins can be determined by magic-anglespinning (MAS) solid-state NMR (§ 1.3.1). Central to most structure determination procedures is the collection of a set of distance restraints that is sufficiently large to achieve convergence in the calculations. Such manual assignment step can form a time-limiting factor in the structure determination process. Due to the effects of spin diffusion in MAS NMR, there are large numbers of cross-peaks in spectra recorded with longer mixing times, which can be highly ambiguous and are difficult to assign consistently when a manual approach is followed. Hence, solid-state NMR structure determination could benefit from automation of the cross-peak assignment and structure calculation procedure. In this Chapter, a strategy for automated protein structure calculation based on solidstate NMR data is presented, making use of concepts known from solution NMR, such as the ARIA protocol for the assignment of ambiguous cross-peaks. For use with solid-state NMR