passages.id: split_6_test_3498_passage
passages.type: progene_text
passages.text: This finding and amino acid sequence comparisons can explain why the MPN - containing proteins Mov34 / PSMD7 , RPN8 , Csn6 , Prp8p and the translation initiation factor 3 subunits f and h do not show catalytic isopeptidase activity , allowing us to propose the hypothesis that in these proteins the MPN domain has a primarily structural function .