Selection rules

Most commands of the CYANA command groups atoms, couplings, shifts, angles, peaks, distances, and structures apply to sets of selected atoms, scalar couplings, chemical shifts, angles, peaks, distance restraints, and structures, respectively. This chapter describes the syntax of the various selections used by CYANA.

Atoms or torsion angles are the basic units of selection. Peaks, distance restraints, and scalar couplings are selected as pairs of atoms, possibly subject to additional conditions. Chemical shifts are selected by the corresponding atom. Torsion angles can be selected in the same way as atoms, using angle names instead of atom names.

Selections can either be volatile, i.e. be used temporarily for the current command, or persistent, i.e. be used for the following commands. Persistent selections are made with the commands atoms select, angles select, angles select, couplings select]], peaks select, and distances select. Selections made by other commands are always volatile.

Structures in memory can be selected with the structure select command. Ranges of numbers in selections, e.g. residue ranges, can be specified in one of the following ways:

m

A number

m..n

A range of numbers

m-n

Alternative format for a range of numbers (only for n ≥ 0)

m..

From number m onwards

m-

From number m onwards; alternative format

..n

From the first up to number n.