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-Structure paper
Title | Structure of the AAA protein Msp1 reveals mechanism of mislocalized membrane protein extraction. |
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Journal, issue, pages | Elife, Vol. 9, Year 2020 |
Publish date | Jan 30, 2020 |
![]() | Lan Wang / Alexander Myasnikov / Xingjie Pan / Peter Walter / ![]() ![]() |
PubMed Abstract | The AAA protein Msp1 extracts mislocalized tail-anchored membrane proteins and targets them for degradation, thus maintaining proper cell organization. How Msp1 selects its substrates and firmly ...The AAA protein Msp1 extracts mislocalized tail-anchored membrane proteins and targets them for degradation, thus maintaining proper cell organization. How Msp1 selects its substrates and firmly engages them during the energetically unfavorable extraction process remains a mystery. To address this question, we solved cryo-EM structures of Msp1-substrate complexes at near-atomic resolution. Akin to other AAA proteins, Msp1 forms hexameric spirals that translocate substrates through a central pore. A singular hydrophobic substrate recruitment site is exposed at the spiral's seam, which we propose positions the substrate for entry into the pore. There, a tight web of aromatic amino acids grips the substrate in a sequence-promiscuous, hydrophobic milieu. Elements at the intersubunit interfaces coordinate ATP hydrolysis with the subunits' positions in the spiral. We present a comprehensive model of Msp1's mechanism, which follows general architectural principles established for other AAA proteins yet specializes Msp1 for its unique role in membrane protein extraction. |
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Methods | EM (single particle) |
Resolution | 3.1 - 3.7 Å |
Structure data | EMDB-20318, PDB-6pdw: EMDB-20319, PDB-6pdy: EMDB-20320, PDB-6pe0: |
Chemicals | ![]() ChemComp-ADP: ![]() ChemComp-BEF: ![]() ChemComp-MG: ![]() ChemComp-ATP: |
Source |
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![]() | PROTEIN TRANSPORT / membrane protein / tail-anchored protein / protein quality control |