Open AccessOn the Binding of tRNA to Escherichia coli RNA Polymerase
Author(s) -
BUSBY Stephen,
SPASSKY Annick,
BUC Henri
Publication year - 1981
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1981.tb05540.x
Subject(s) - transfer rna , dna , dna polymerase , enzyme , polymerase , dna clamp , biochemistry , dimer , chemistry , ternary complex , rna , biology , microbiology and biotechnology , reverse transcriptase , gene , organic chemistry
We have investigated the interplay between the binding of tRNA and DNA to core RNA polymerase. We show that the monomer core enzyme can bind stably to either DNA or tRNA, whereas the dimer core can fix both DNA and tRNA in a stable ternary complex. We have examined the kinetics of the exchange between DNA and tRNA bound to the core enzyme. DNA bound to monomer core can be rapidly displaced by tRNA without prior dissociation of the core from the DNA. Similarly tRNA bound to the core can be displaced by DNA without prior dissociation of the tRNA. We confirm the result of Hinkle and Chamberlin [ J. Mol. Biol. 70 , 157–185 (1972)] that, in contrast, the core enzyme must first dissociate from one DNA molecule before it can transfer to another DNA. As this dissociation is very slow we suggest that, in vivo, the tRNA can act as a ‘porter’ providing the core enzyme with a more kinetically favourable path to transfer from one DNA site to another.