Optimal efficiency of ClpAP and ClpXP chaperone-proteases is achieved by architectural symmetry.

Maglica Z; Kolygo K; Weber-Ban E

doi:10.1016/j.str.2009.02.014

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Journal article

Optimal efficiency of ClpAP and ClpXP chaperone-proteases is achieved by architectural symmetry.

Maglica Z Institute of Molecular Biology and Biophysics, ETH Zürich, CH-8093 Zürich, Switzerland.
Kolygo K
Weber-Ban E

2009-04-17

Published in:

Structure (London, England : 1993). - 2009

ATPases Associated with Diverse Cellular Activities

Fluorescence Resonance Energy Transfer

Spectrophotometry, Ultraviolet

English A common feature of chaperone-proteases is architectural two-fold symmetry across the proteolytic cylinder. Here we investigate the role of symmetry for the function of ClpAP and ClpXP assemblies. We generated asymmetric ClpP particles in which the two rings differ in ClpA and ClpX binding capability and/or in proteolytic activity. Rapid-kinetic fluorescence measurements and steady-state experiments indicate that single 2:1 ClpAP or ClpXP complexes are as efficient in substrate degradation as two 1:1 ClpAP or ClpXP assemblies. This implies that the two chaperone components work independently. However, an asymmetric ClpP particle composed of one active and one inactive ring can stimulate ATPase activity of ClpA regardless of whether ClpA binds to the active ring or to the opposite side of ClpP, across the ring of inactivated protease. Thus, we propose that conformational transitions in ClpP are concerted and allosteric effects are transferred simultaneously to both associated chaperones, leading to synchronized activation.

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