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Title | ClpL is a functionally active tetradecameric AAA+ chaperone, distinct from hexameric/dodecameric ones. |
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Journal, issue, pages | FASEB J, Vol. 34, Issue 11, Page 14353-14370, Year 2020 |
Publish date | Sep 10, 2020 |
Authors | Gyuhee Kim / Seong-Gyu Lee / Seungsu Han / Jaeeun Jung / Hyeong Seop Jeong / Jae-Kyung Hyun / Dong-Kwon Rhee / Ho Min Kim / Sangho Lee / |
PubMed Abstract | AAA+ (ATPases associated with diverse cellular activities) chaperones are involved in a plethora of cellular activities to ensure protein homeostasis. The function of AAA+ chaperones is mostly ...AAA+ (ATPases associated with diverse cellular activities) chaperones are involved in a plethora of cellular activities to ensure protein homeostasis. The function of AAA+ chaperones is mostly modulated by their hexameric/dodecameric quaternary structures. Here we report the structural and biochemical characterizations of a tetradecameric AAA+ chaperone, ClpL from Streptococcus pneumoniae. ClpL exists as a tetradecamer in solution in the presence of ATP. The cryo-EM structure of ClpL at 4.5 Å resolution reveals a striking tetradecameric arrangement. Solution structures of ClpL derived from small-angle X-ray scattering data suggest that the tetradecameric ClpL could assume a spiral conformation found in active hexameric/dodecameric AAA+ chaperone structures. Vertical positioning of the middle domain accounts for the head-to-head arrangement of two heptameric rings. Biochemical activity assays with site-directed mutagenesis confirmed the critical roles of residues both in the integrity of the tetradecameric arrangement and activities of ClpL. Non-conserved Q321 and R670 are crucial in the heptameric ring assembly of ClpL. These results establish that ClpL is a functionally active tetradecamer, clearly distinct from hexameric/dodecameric AAA+ chaperones. |
External links | FASEB J / PubMed:32910525 |
Methods | EM (single particle) |
Resolution | 4.5 - 6.33 Å |
Structure data | |
Chemicals | ChemComp-MG: ChemComp-AGS: |
Source |
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Keywords | CHAPERONE / AAA+ ATPase / Streptococcus pneumoniae / ClpL |