Neurophysin tetramer with dipeptide(hormone analogue) bound to it. There are five dipeptides per tetramer, four(shown in blue) bind at the major hormone-binding site while the fifth one (light blue) straddles one of the monomer-monomer interfaces.
(Left) The Ca backbone of a tetramer viewed along its pseudo two-fold axis.
(Right) Space-filling drawing of a tetramer showing that one pair of Tyr49 (orange) is near the dimer-dimer interface.
