Partial Structure Factors

In the following example, the structure factors of residues 1 and 2 are computed and written along with to the file “partial.data":

xrefin ... reflection @fobs.fob end selection=( resid 1:2 ) update do (FPART=FCALC) write reflection fobs fpart output=partial.data end end

In the next example, the partial structure factors are read, the structure factors of the remaining residues are computed, and for whole structure is computed:

xrefin ... reflection reset @partial.data end selection=( not ( resid 1:2 ) ) update print rfactor end

In addition, one should fix the frozen atoms during minimization and dynamics by including the statement

constraints fix=( resid 1:2 ) endbefore running minimization or dynamics. One should use “method=direct" instead of “method=FFT" if the frozen part contains more than 80% of the molecule.