CYANA Command: distances split

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Parameters

selection=distance restraint selection
(default: none)
keep=real
(default: 0.25)
exponent=real
(default: 6.0)
extension=real
(default: 1.0)

Description

Splits suitable ambiguous distance restraints that match the given selection into several unambiguous distance restraints. 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. Each of the new distance restraints will be assigned uniquely to one of the multiple assignments of the ambiguous input restraint. The upper distance bound u' of a new restraint is obtained from the upper bound u of the corresponding ambiguous input restraint according to the formula

 u' = u [1 + f ((V'/V)(-1/n) - 1)],

where f=extension, n=exponent, and V'/V is the fraction of the total NOESY cross peak volume of the original ambiguous restraint that originates from the single assignment of the new restraint.
This volume contribution is computed for each selected structure by assuming a r-6 distance-to-volume relationship. The average over all conformers of these volume contributions is used for the fraction V'/V. Only assignments for which V'/V>keep are kept to generate an unambiguous distance restraint, others are discarded.