8ET3

Cryo-EM structure of a delivery complex containing the SspB adaptor, an ssrA-tagged substrate, and the AAA+ ClpXP protease

8ET3 の概要

• エントリーDOI: 10.2210/pdb8et3/pdb
• EMDBエントリー: 28585
• 分子名称: ATP-dependent Clp protease ATP-binding subunit ClpX, ATP-dependent Clp protease proteolytic subunit, Green fluorescent protein, ... (6 entities in total)
• 機能のキーワード: aaa+ protease, clpxp, sspb adaptor, hydrolase, chaperone
• 由来する生物種: Escherichia coli; 詳細
• タンパク質・核酸の鎖数: 16
• 化学式量合計: 513132.69

構造登録者

Ghanbarpour, A.,Fei, X.,Davis, J.H.,Sauer, R.T. (登録日: 2022-10-16, 公開日: 2023-01-25, 最終更新日: 2024-06-19)

主引用文献

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

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: 36730206
DOI: 10.1073/pnas.2219044120

実験手法

ELECTRON MICROSCOPY (3.7 Å)