passages.id: split_6_test_3013_passage
passages.type: progene_text
passages.text: In order to further dissect the role of the linker region , three residues ( Ala257 , Pro259 , and Asp263 ) that was disordered in the crystal structure of the hexameric helicase fragment were substituted with all amino acids , and the altered proteins were analyzed for their ability to support growth of T7 phage lacking gene 4 .