Structural highlights
Function
[TIG_ECOLI] Involved in protein export. Acts as a chaperone by maintaining the newly synthesized secretory and non-secretory proteins in an open conformation. Binds to nascent polypeptide chains via ribosomal protein L23 (PubMed:12226666). Functions as a peptidyl-prolyl cis-trans isomerase in vitro, this activity is dispensible in vivo for chaperone activity.[1] [2] [3]
Publication Abstract from PubMed
Molecular chaperones alter the folding properties of cellular proteins via mechanisms that are not well understood. Here, we show that Trigger Factor (TF), an ATP-independent chaperone, exerts strikingly contrasting effects on the folding of non-native proteins as it transitions between a monomeric and a dimeric state. We used NMR spectroscopy to determine the atomic resolution structure of the 100 kDa dimeric TF. The structural data show that some of the substrate-binding sites are buried in the dimeric interface, explaining the lower affinity for protein substrates of the dimeric compared to the monomeric TF. Surprisingly, the dimeric TF associates faster with proteins and it exhibits stronger anti-aggregation and holdase activity than the monomeric TF. The structural data show that the dimer assembles in a way that substrate-binding sites in the two subunits form a large contiguous surface inside a cavity, thus accounting for the observed accelerated association with unfolded proteins. Our results demonstrate how the activity of a chaperone can be modulated to provide distinct functional outcomes in the cell.
Oligomerization of a molecular chaperone modulates its activity.,Saio T, Kawagoe S, Ishimori K, Kalodimos CG Elife. 2018 May 1;7. pii: 35731. doi: 10.7554/eLife.35731. PMID:29714686[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Hesterkamp T, Hauser S, Lutcke H, Bukau B. Escherichia coli trigger factor is a prolyl isomerase that associates with nascent polypeptide chains. Proc Natl Acad Sci U S A. 1996 Apr 30;93(9):4437-41. PMID:8633085
- ↑ Valent QA, Kendall DA, High S, Kusters R, Oudega B, Luirink J. Early events in preprotein recognition in E. coli: interaction of SRP and trigger factor with nascent polypeptides. EMBO J. 1995 Nov 15;14(22):5494-505. PMID:8521806
- ↑ Genevaux P, Keppel F, Schwager F, Langendijk-Genevaux PS, Hartl FU, Georgopoulos C. In vivo analysis of the overlapping functions of DnaK and trigger factor. EMBO Rep. 2004 Feb;5(2):195-200. Epub 2004 Jan 9. PMID:14726952 doi:10.1038/sj.embor.7400067
- ↑ Saio T, Kawagoe S, Ishimori K, Kalodimos CG. Oligomerization of a molecular chaperone modulates its activity. Elife. 2018 May 1;7. pii: 35731. doi: 10.7554/eLife.35731. PMID:29714686 doi:http://dx.doi.org/10.7554/eLife.35731
