8ET3
Cryo-EM structure of a delivery complex containing the SspB adaptor, an ssrA-tagged substrate, and the AAA+ ClpXP protease
Summary for 8ET3
| Entry DOI | 10.2210/pdb8et3/pdb |
| EMDB information | 28585 |
| Descriptor | ATP-dependent Clp protease ATP-binding subunit ClpX, ATP-dependent Clp protease proteolytic subunit, Green fluorescent protein, ... (6 entities in total) |
| Functional Keywords | aaa+ protease, clpxp, sspb adaptor, hydrolase, chaperone |
| Biological source | Escherichia coli More |
| Total number of polymer chains | 16 |
| Total formula weight | 513132.69 |
| Authors | Ghanbarpour, A.,Fei, X.,Davis, J.H.,Sauer, R.T. (deposition date: 2022-10-16, release date: 2023-01-25, Last modification date: 2024-06-19) |
| Primary citation | Ghanbarpour, A.,Fei, X.,Baker, T.A.,Davis, J.H.,Sauer, R.T. The SspB adaptor drives structural changes in the AAA+ ClpXP protease during ssrA-tagged substrate delivery. Proc.Natl.Acad.Sci.USA, 120:e2219044120-e2219044120, 2023 Cited by PubMed Abstract: Energy-dependent protein degradation by the AAA+ ClpXP protease helps maintain protein homeostasis in bacteria and eukaryotic organelles of bacterial origin. In and many other proteobacteria, the SspB adaptor assists ClpXP in degrading ssrA-tagged polypeptides produced as a consequence of tmRNA-mediated ribosome rescue. By tethering these incomplete ssrA-tagged proteins to ClpXP, SspB facilitates their efficient degradation at low substrate concentrations. How this process occurs structurally is unknown. Here, we present a cryo-EM structure of the SspB adaptor bound to a GFP-ssrA substrate and to ClpXP. This structure provides evidence for simultaneous contacts of SspB and ClpX with the ssrA tag within the tethering complex, allowing direct substrate handoff concomitant with the initiation of substrate translocation. Furthermore, our structure reveals that binding of the substrate·adaptor complex induces unexpected conformational changes within the spiral structure of the AAA+ ClpX hexamer and its interaction with the ClpP tetradecamer. PubMed: 36730206DOI: 10.1073/pnas.2219044120 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3.7 Å) |
Structure validation
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