CYANA Command: distances stereoexpand

Parameters

selection=string

(default: none)

shrink

Description

This command replaces in the distance restraints that match the selection string the diastereotopic substitutents that are not stereospecificly assigned by their corresponding pseudoatoms. By default, the selection made in the most recent distances select command is used, or all distance restraints if no selection has been made so far.

If the option shrink is set, a pseudoatom correction is added to the upper distance bound. The corrected upper distance bound u is calculated from the original upper bound u according to the formula

 u = (u^-6 + (u + c1)^-6 + (u + c2)^-6 + (u + c1 + c2)^-6)^(-1/6),

where c1 denotes the distance between the first diatereotopic substituent and its corresponding pseudoatom, and c2 denotes the distance between the second diatereotopic substituent and its corresponding pseudoatom. If the first or the second atom involved in the restraint are not diastereotopic substitutents, or stereospecificly assigned, then the corresponding terms that involve c1 and c2 are omitted from the sum in the formula for u.