Optimal efficiency of ClpAP and ClpXP chaperone-proteases is achieved by architectural symmetry.
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.
Institute of Molecular Biology and Biophysics, ETH Zürich, CH-8093 Zürich, Switzerland.
Zeljka
Z
Maglica
Kristina
K
Kolygo
Eilika
E
Weber-Ban
D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D001665:Binding Sites / Q000235:genetics; D002384:Catalysis; D049071:Endopeptidase Clp / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D031541:Fluorescence Resonance Energy Transfer; D007700:Kinetics; D008027:Light; D018832:Molecular Chaperones / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D011485:Protein Binding / Q000235:genetics; D012542:Scattering, Radiation; D013056:Spectrophotometry, Ultraviolet; D013379:Substrate Specificity
D029968:Escherichia coli Proteins; D018832:Molecular Chaperones; C483568:ClpA protease, E coli; D049071:Endopeptidase Clp; D000251:Adenosine Triphosphatases; C088072:ClpX protein, E coli; D000074183:ATPases Associated with Diverse Cellular Activities