passages.id: split_4_test_39_passage
passages.type: progene_text
passages.text: In the Pit-1 POU domain homodimer the dimerization interface is formed between the C - terminal end of helix 3 of the POU - homeodomain of one Pit-1 molecule and the N - terminus of helix 1 and the loop between helices 3 and 4 of the POU - specific domain of the other Pit-1 molecule .