In addition to the descriptive material below, you may view our interactive models. For instructions on how to manipulate the structures on-screen, see Eric Martz's Chime Pages .
Experimental evidence indicates that the protein forms a functional dimer.
In constructing models of the transmembrane helical portion of the protein, we have considered four types of arrangements. Careful examination of TMD-3 suggested to us the possibility that this helix could form a part of the dimer interface. The type 3 model has a clockwise arrangement. We have examined the corresponding counterclockwise arrangement, which we have designated type 4 . The models can suggest experiments which will aid in determining the transporter structure.