Continuous compact protein domains

The coefficient of compactness was recently introduced and used to locate domains in lysozyme and ribonuclease (Zehfus and Rose: Biochemistry 25:5759-5765, 1986). Nineteen additional proteins now have been analyzed by using this measure. Complete listings of compact units and plots showing their hierarchic organization are presented for all twenty-one proteins. Large compact units correspond well to protein domains; however, many smaller compact structures of equal or better compactness are also found. Since small compact units could represent subdomains or protein-folding intermediates, their structural composition is further examined.