In this study , we demonstrate reconstitution of a cell-free processing system and demonstrate directly that : ( a ) the ubiquitin -proteasome system is involved in processing of the intact p105 precursor , ( b ) conjugation of ubiquitin to the precursor is an essential intermediate step in the processing , ( c ) the recently discovered novel species of the ubiquitin -carrier protein , E2-F1 , that is involved in the conjugation and degradation of p53 , is also required for the limited processing of the p105 precursor , and ( d ) a novel , approximately 320-kDa species of ubiquitin -protein ligase , is involved in the process .
in this study , we demonstrate reconstitution of a cell-free processing system and demonstrate directly that : ( a ) the ubiquitin -proteasome system is involved in processing of the intact p105 precursor , ( b ) conjugation of ubiquitin to the precursor is an essential intermediate step in the processing , ( c ) the recently discovered novel species of the ubiquitin -carrier protein , e2-f1 , that is involved in the conjugation and degradation of p53 , is also required for the limited processing of the p105 precursor , and ( d ) a novel , approximately 320-kda species of ubiquitin -protein ligase , is involved in the process .
O O O O O O O O O B-other_name I-other_name I-other_name O O O O O O O O O B-protein_molecule B-protein_complex O O O O O O O O B-protein_molecule O O O O O O O B-protein_molecule O O O O O O O O O O O O O O O O O O O O O O B-protein_molecule O O O B-protein_molecule O O O O O O O O O O B-protein_subunit O O O O O O O O O O B-protein_molecule I-protein_molecule O O O O O O O O O B-protein_molecule I-protein_molecule O B-protein_molecule O O O O O O O O O