Suno Ryoji, Taguchi Hideki, Masui Ryoji, Odaka Masafumi, Yoshida Masasuke
Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama 226-8503, Japan.
J Biol Chem. 2004 Feb 20;279(8):6380-4. doi: 10.1074/jbc.M311572200. Epub 2003 Nov 5.
The ribosome-associated chaperone trigger factor (TF) of Escherichia coli interacts with a variety of newly synthesized polypeptides to assist their correct folding. Here, we report that the TF of thermophilic eubacterium, Thermus thermophilus, arrested spontaneous folding of green fluorescent protein by forming a 1:1 binary complex. The complex was isolable by gel-filtration but was shown to be dynamic because green fluorescent protein was released by alpha-casein in large excess. Unexpectedly, EDTA completely abolished the folding-arrest activity of TF, and analysis revealed that the TF from our preparation contained approximately 0.5 mol Zn2+/mol TF. The folding-arrest activity of TF that was saturated with Zn2+ (approximately 1 mol/mol TF) was twice as efficient as that of untreated TF. Thus, chaperone activity of thermophilic TF is Zn2+-dependent.
