Assigning secondary structure from protein coordinate data.

We have developed a program to convert the three dimensional coordinates describing protein structure in the Brookhaven Data Bank into an assignment of secondary structure. The program assigns secondary structure in the same way a person assigns structure visually. It uses two angles and three distances to assign alpha-helix, 3(10)-helix, beta-strand, hydrogen-bonded beta-turn, non-hydrogen-bonded beta-turn, and poly (L-proline) II type 3(1)-helix. The program is concerned with amide-amide interactions and should be particularly useful to spectroscopists.