Volume 2 Chapter 3 3D-Constrain Sub-menu DEL-INSTRUCTIONS

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When a torsion angle is being tested for a selected range of values, specified by the SELECT command, if the test fails the fragment is inverted and tested again to determine whether the fragment is to be declared a hit.

The corresponding command in the instruction document is: ENANT INVE


Consider the following fragment in which the torsion angle TA1 has been defined as:

TA1 5 4 1 X1

Six entries in the database which contain this fragment are listed below with the values of TA1 and the space groups of the structures:

REFCODE        TA1 (FRAG 1)     TA1 (FRAG 2)         SPACE GROUP
ACMEPT10      -176.205          176.188                 P21/c
ACOHKT         -75.168           21.613                 P-1
AIMCTY        -146.695                                  P212121
ALCHRB10       -20.191                                  P21
ARITOL         150.295                                  P32
BARTUS10       -10.475                                  P21
If TA1 has been selected to lie in the range 140 to 160 degrees then a search with INVERT active

(ie. command ENANT INVE in the instruction document) will hit AIMCTY and ARITOL.

Note that when the fragment is inverted all parameters are recalculated. Torsion angles are the most common enantiomorph-sensitive parameters.

Related Commands


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Volume 2 Chapter 3 3D-Constrain Sub-menu ENANTIOMER NOINVERT.