Structural comparison of lactose permease and the glycerol-3-phosphate antiporter: members of the major facilitator superfamily.

Structural knowledge of the major facilitator superfamily has dramatically increased during the past year with the emergence of the structures of three members of this family of transporters. All three structures reveal 12 transmembrane helices forming two distinct domains, and could imply that members of this superfamily have preserved both secondary and tertiary structure elements during evolution.