A. Diagram showing a helical pattern of this class. B. Example of the class, hemoglobin, PDB file 3hhb displayed using Rasmol, using ribbons display and group color. A. B. 3hhb 2. Class b is comprised of antiparallel b sheets, usually two sheets in close contact forming a sandwich. Alternatively, a sheet can twist into a barrrel with the first and last strands touching.
Examples are enzymes, transport proteins, antibodies, and virus coat proteins such as neuraminidase.
Structure of b class proteins. This class of proteins includes many metabolic enzymes. Membrane and cell surface proteins and peptides excluding proteins of the immune system. Structure of membrane proteins. Membrane bilayer shown as green lines.