The NOE statement sets up the database for distance
restraints, such as interproton distances. This database
is used to evaluate 
, which can be combined with
other energy terms (see Chapter 4).
The
resulting hybrid energy function can be used for
simulated annealing or minimization,
using the methods described in Chapters 9 and
10.
(Example protocols for
NMR structure determination are described in Chapter
20.)
For further reading, see Brünger (1991b), Brünger et al. (1986), Brünger et al. (1987), Brünger and Karplus (1991), Clore and Gronenborn (1989, 1991), Kaptein et al. (1985), Nilges, Clore, and Gronenborn (1988a, 1988b), Nilges, Gronenborn, and Clore (1989), and Nilsson et al. (1986).
It should be noted that the NOE facility in X-PLOR can be used to restrain any type of distance between selected atoms; e.g., it is possible to restrain the characteristic hydrogen-bonding pattern of secondary structural elements by using the NOE statement.