ClpL is a functionally active tetradecameric AAA+ chaperone, distinct from hexameric/dodecameric ones.
FASEB J
; 34(11): 14353-14370, 2020 11.
Article
en En
| MEDLINE
| ID: mdl-32910525
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 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.
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Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Proteínas Bacterianas
/
Chaperonas Moleculares
/
Multimerización de Proteína
Idioma:
En
Revista:
FASEB J
Asunto de la revista:
BIOLOGIA
/
FISIOLOGIA
Año:
2020
Tipo del documento:
Article