When setting distance constraints in the standalone version of I-TASSER:
1. If I were to specify a distance of, say, 5 A between two specific atoms, what is the +/- range on this number? Is it possible to specify a range or to use "greater than" (>) or "less than" (<)?
2. If I were to specify that two residues should be "in contact", what is the range of distances that constitute a "contact"?
3. Is it possible to use "contact" for two atoms rather than two residues, or is it necessary to specify a distance in Angstroms for atoms?