Preferences of the side chains in proteins for helix, beta strand, turn, and other conformations. Secondary structures of copper proteins

Statistical preferences of the side chains in proteins for the helical conformation, the β strand conformation, and the turn conformation were derived from the computer-assigned secondary structures of 55 protein chains reported by Levitt and Greer in 1977 after averaging redundant structures and weighting structures that showed > 25 % homology by w = ▪. Separate preferences are reported for free cysteine side chains and for cystine. These preferences are used to predict the secondary structures of cucumber plastocyanin and cupredoxin, whose crystal structures will be reported soon. The loops in the C-terminal copper-binding regions are discussed.