title: An initiation factor causing dissociation of E. coli ribosomes.
abstract: Purification of crude initiation factors, essential for polypeptide synthesis in cell-free systems of E. coli, yielded a fraction DF which causes dissociation of 70 S ribosomes. Its stoichiometric action on 70 S ribosomes is antagonized by increasing Mg(2+) concentrations but not by the addition of 30 S and 50 S subunits washed with high salt concentration. GTP did not stimulate this dissociating action. 2 &mgr;g of our most purified preparation caused 100% dissociation of 100 &mgr;g of 70 S ribosomes without added GTP. DF-induced dissociation is a very rapid process at 37 degrees C and is temperature-dependent in the range of 0 degrees -37 degrees C. DF, which is thermolabile factor, is much less or not effective with complexed 70 S ribosomes bearing peptidyl-tRNA and mRNA.
authors.affiliation: Department of Biochemistry, University of Leiden, The Netherlands
authors.forename: J
authors.initials: J
authors.lastname: Albrecht
authors.forename: F
authors.initials: F
authors.lastname: Stap
authors.forename: H O.
authors.initials: HO
authors.lastname: Voorma
authors.forename: P H.
authors.initials: PH
authors.lastname: Van Knippenberg
authors.forename: L
authors.initials: L
authors.lastname: Bosch