Effect of directional pulling on mechanical protein degradation by ATP-dependent proteolytic machines.
| Autor: | Olivares AO; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139., Kotamarthi HC; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139.; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139., Stein BJ; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139., Sauer RT; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139; bobsauer@mit.edu tabaker@mit.edu., Baker TA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139; bobsauer@mit.edu tabaker@mit.edu.; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139. |
|---|---|
| Jazyk: | angličtina |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2017 Aug 01; Vol. 114 (31), pp. E6306-E6313. Date of Electronic Publication: 2017 Jul 19. |
| DOI: | 10.1073/pnas.1707794114 |
| Abstrakt: | AAA+ proteases and remodeling machines couple hydrolysis of ATP to mechanical unfolding and translocation of proteins following recognition of sequence tags called degrons. Here, we use single-molecule optical trapping to determine the mechanochemistry of two AAA+ proteases, Escherichia coli ClpXP and ClpAP, as they unfold and translocate substrates containing multiple copies of the titin I27 domain during degradation initiated from the N terminus. Previous studies characterized degradation of related substrates with C-terminal degrons. We find that ClpXP and ClpAP unfold the wild-type titin I27 domain and a destabilized variant far more rapidly when pulling from the N terminus, whereas translocation speed is reduced only modestly in the N-to-C direction. These measurements establish the role of directionality in mechanical protein degradation, show that degron placement can change whether unfolding or translocation is rate limiting, and establish that one or a few power strokes are sufficient to unfold some protein domains. Competing Interests: The authors declare no conflict of interest. |
| Databáze: | MEDLINE |
| Externí odkaz: |
|