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Newly folded substrates inside the molecular cage of the HtrA chaperone DegQ

Malet, Hélène and Canellas, F. and Sawa, J. and Yang, J. and Thalassinos, Konstantinos and Ehrmann, M. and Clausen, T. and Saibil, Helen R. (2012) Newly folded substrates inside the molecular cage of the HtrA chaperone DegQ. Nature Structural & Molecular Biology 19 , pp. 152-157. ISSN 1545-9993.

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Official URL: http://dx.doi.org/10.1038/nsmb.2210

Abstract

The HtrA protein family combines chaperone and protease activities and is essential for protein quality control in many organisms. Whereas the mechanisms underlying the proteolytic function of HtrA proteins are well characterized, their chaperone activity remains poorly understood. Here we describe cryo-EM structures of Escherichia coli DegQ in its 12- and 24-mer states in complex with model substrates, providing a structural model of HtrA chaperone action. Up to six lysozyme substrates bind inside the DegQ 12-mer cage and are visualized in a close-to-native state. An asymmetric reconstruction reveals the binding of a well-ordered lysozyme to four DegQ protomers. DegQ PDZ domains are located adjacent to substrate density and their presence is required for chaperone activity. The substrate-interacting regions appear conserved in 12- and 24-mer cages, suggesting a common mechanism of chaperone function.

Item Type: Article
School or Research Centre: Birkbeck Schools and Research Centres > School of Science > Biological Sciences
Depositing User: Administrator
Date Deposited: 17 Jan 2012 11:00
Last Modified: 08 May 2013 08:45
URI: http://eprints.bbk.ac.uk/id/eprint/4568

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