This menu is an aid to map interpretation. It allows one to make an estimate of what amino acid is to be associated with some electron density. The user enters a guess of the sequence based on the shape and position of the density that is then compared to the actual sequence via a look up table that must have been read into the users database. The guess may be accepted and may be entered into the database as a named entity. A number of guesses can later be combined together.
The guesses entered are one letter codes that usually appear to be the 20 amino acids. However, any one letter can be entered but it must exist in the `slider matrix' that converts the entered symbol into a score relative to each of the 20 amino acids. The user is free to modify the file supplied in $ODAT/slider.o --- it is NOT based simply on matching the size of the sequence to the guess.