# VEN, VENN

NAME
VEN, VENN - draw Venn diagram.
SYNOPSIS
VEN
VEN OFF
VEN start_index end_index
VENN
VENN OFF
VENN start_index end_index
DESCRIPTION
Draw Venn diagram for the given protein sequence or sequence fragment. Venn diagram gives the quick statistical overview of the protein sequence: count of residues and residue types. It is primarily intended for students. Experts will not find this routine very interesting.
KEYWORDS AND PARAMETERS
The command VENN may be used alone, combined with the keyword OFF or with two residue numbers. Note that from version 1.4, residue array indices are used instead of serial indices! There was some mess with the structures which consist of multiple chains, so the actual residue numbers (related to array indices) proved to be more reliable than the serial numbers. If you specify the residue range from 1 to 100, the residues having the array indices between 0 and 99 will be used. This is because the lowest array index in the C programming language is zero, not one.
If used alone, the Venn diagram will be drawn for the entire sequence stored in the main sequence buffer. Two residue array indices (shifted for one) may be used to specify the residue range. The keyword OFF is used to return to the main drawing mode (structure drawing mode).
EXAMPLES

COMMAND | DESCRIPTION
load 2por.pdb seq from 1 ven | Load the specified structure (porin), copy the sequence from this structure to the main sequence buffer and draw Venn diagram.
ven 1-100 | Prepare Venn diagram with counts, but only for the first hundred residues, having the array indices from 0 to 99.
ven off | Return to default drawing mode. Instead using this command, you can hit the ESCAPE key.

NOTES
(1) Instead using the command VENN OFF, the ESCAPE key may be pressed to return to the main drawing mode.
(2) Ven diagram is a term from the set theory, which is part of mathematics. Different sorts of Venn diagrams may be found in different branches of science.
RELATED COMMANDS
SEQUENCE is used to copy, define or load the sequence.