W. Kudlicki et al., BINDING OF AN N-TERMINAL RHODANESE PEPTIDE TO DNAJ AND TO RIBOSOMES, The Journal of biological chemistry, 271(49), 1996, pp. 31160-31165
A peptide corresponding to the N-terminal 17 amino acids of bovine rho
danese was fluorescently labeled with a coumarin derivative at its pri
mary amino group(s) and then purified by high performance liquid chrom
atography. This peptide interacted with the molecular chaperone DnaJ i
n the absence of other chaperones and ATP, In the presence of ATP, the
molecular chaperone DnaK bound to the DnaJ-peptide complex, but not t
o the peptide alone, The chaperone GrpE appeared to cause the release
of the peptide bound to the ternary complex in the presence of ATP but
not in the presence of ADP, This nucleotide apparently stabilized the
complex, The peptide also bound to salt-washed Escherichia coli 70 S
ribosomes, specifically to 50 S ribosomal subunits, not to 30 S subuni
ts, DnaJ plus DnaK interacted with the peptide on the ribosome, GrpE c
aused dissociation of the peptide from the ribosome; ATP was required
for this reaction, It was inhibited by ADP, A comparable series of cha
perone-mediated reactions is assumed to occur with the N-terminal segm
ent of the nascent polypeptide to facilitate its folding on ribosomes.