|The ribbon structure of the Salmonella bacterial flagellin protein. This protein self-assembles by non-covalent interactions into helical flagella fibers composed of up to 30,000 monomers, with assistance provided by the FliD chaperonin protein complex bound on the end of the fibers. These flagella fibers are rotated by a membrane-bound rotary motor to provide propulsion for many types of bacteria. The middle region of this protein sequence varies greatly between species while the ends are highly conserved.
||The ribbon structure of the archaeal gamma-class carbonic anhydrase (Cam). This is a trimeric enzyme that may use iron instead of zinc, and has structural analogs in other microorganisms, including E. coli.
||The ribbon structure of the alpha-class mammalian carbonic anhydrase II (CA II). This is a monomeric zinc enzyme with one of the fastest catalytic rates known. At least 14 isozymes of this enzyme are known in mammals; some of which are the targets of some sulfonamide drugs in the treatment of glaucoma and high altitude sickness and some types of cancer.