Contents

24 August 1990
Vol 249, Issue 4971

About The Cover

Artistic representation of the secondary structure prediction from a neural network analysis of the principal neutralization determinant of HIV-1. The sheets are shown by arrows and helices by spirals. See page 932. [Illustration by Elizabeth Bothwell, Gregory LaRosa, and Scott Putney; neural network analysis by L. Howard Holley and Martin Karplus]