Dissociation of the GroEL−GroES Asymmetric Complex Is Accelerated by Increased Cooperativity in ATP Binding to the GroEL Ring Distal to GroES

Fridmann, Yael; Kafri, Galit; Danziger, Oded; Horovitz, Amnon

doi:10.1021/bi020117v

Cited by 19 publications

(16 citation statements)

References 31 publications

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“…ii) We and others (17)(18)(19) ] or adding SP reduces the affinity of the trans ring for ADP and promotes its reversion to the T state, a necessary condition for additional catalytic cycling. Because the T state of GroEL D83A/R197A has been destabilized by removal of the salt bridges, it was to be expected that the ATP-induced dissociation of GroES from the cis ring would be inhibited.…”

Section: Significancementioning

confidence: 99%

Crystal structure of a GroEL-ADP complex in the relaxed allosteric state at 2.7 Å resolution

Yang

LaRonde-LeBlanc³

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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The chaperonin proteins GroEL and GroES are cellular nanomachines driven by the hydrolysis of ATP that facilitate the folding of structurally diverse substrate proteins. In response to ligand binding, the subunits of a ring cycle in a concerted manner through a series of allosteric states (T, R, and R″), enabling work to be performed on the substrate protein. Removing two salt bridges that ordinarily break during the allosteric transitions of the WT permitted the structure of GroEL-ADP in the R state to be solved to 2.7 Å resolution. Whereas the equatorial domain displays almost perfect sevenfold symmetry, the apical domains, to which substrate proteins bind, and to a lesser extent, the intermediate domains display a remarkable asymmetry. Freed of intersubunit contacts, the apical domain of each subunit adopts a different conformation, suggesting a flexibility that permits interaction with diverse substrate proteins. This result contrasts with a previous cryo-EM study of a related allosteric ATP-bound state at lower resolution. After artificially imposing sevenfold symmetry it was concluded that a GroEL ring in the R-ATP state existed in six homogeneous but slightly different states. By imposing sevenfold symmetry on each of the subunits of the crystal structure of GroEL-ADP, we showed that the synthetic rings of (X-ray) GroEL-ADP and (cryo-EM) GroEL-ATP are structurally closely related. A deterministic model, the click stop mechanism, that implied temporal transitions between these states was proposed. Here, however, these conformational states are shown to exist as a structurally heterogeneous ensemble within a single ring.protein machine | allostery | chaperonin T o assist protein folding, the GroEL/GroES chaperonin machine cycles through a series of conformational states in response to ligand binding (1-3). Two states, taut (T) and relaxed (R), are populated in the absence of GroES. Another two states, R′ and R″, that exist before and after ATP hydrolysis, respectively, are populated on GroES binding to the R state (1-3) (Fig. 1A). Crystal structures of T [Protein Data Bank (PDB) ID code 1OEL] (4) (PDB ID code 1XCK) (5), R′ (PDB ID code 1SVT) (6), and R″ (PDB ID code 1AON) (7) states are available.As described by the theory of nested cooperativity, the conformational transitions within each heptameric ring are positively cooperative, whereas the transitions between the rings are negatively cooperative (8, 9). Multiple salt bridges, some within a subunit and others between subunits, stabilize these various conformational states. In such a dynamic system, these salt bridges must continually be broken and reformed at different points during the chaperonin cycle. Two interdomain salt bridges, an intrasubunit one (D83-K327) and an intersubunit one (R197-E386), stabilize the T state and are ordinarily broken during the T to R transition that follows the binding of ATP to the WT (Fig. 1B). Individually, the R197A mutation destabilizes the T state (10, 11), whereas replacing the D83-K327 salt bridge with a disulfid...

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Section: Significancementioning

confidence: 99%

Crystal structure of a GroEL-ADP complex in the relaxed allosteric state at 2.7 Å resolution

Yang

LaRonde-LeBlanc³

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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“…Stopped-flow Analysis of Temperature-dependent Conformational Changes-Recent studies have attempted to characterize the specific conformational changes of GroEL during its functional mechanism using extremely rapid spectrophotometric methods (13,(25)(26)(27)(28). In the present case, the introduced tryptophan provides an ideal conformational probe for such studies, and an interesting comparison could be made at the two different experimental temperatures.…”

Section: Cis-ternary Complex and Chaperonin Functionmentioning

confidence: 99%

GroEL-Substrate-GroES Ternary Complexes Are an Important Transient Intermediate of the Chaperonin Cycle

Miyazaki

Yoshimi

Furutsu

et al. 2002

Journal of Biological Chemistry

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GroEL C138W is a mutant form of Escherichia coliGroEL, which forms an arrested ternary complex composed of GroEL, the co-chaperonin GroES and the refolding protein molecule rhodanese at 25°C. This state of arrest could be reversed with a simple increase in temperature. In this study, we found that GroEL C138W formed both stable trans-and cis-ternary complexes with a number of refolding proteins in addition to bovine rhodanese. These complexes could be reactivated by a temperature shift to obtain active refolded protein.The simultaneous binding of GroES and substrate to the cis ring suggested that an efficient transfer of substrate protein into the GroEL central cavity was assured by the binding of GroES prior to complete substrate release from the apical domain. Stopped-flow fluorescence spectroscopy of the mutant chaperonin revealed a temperature-dependent conformational change in GroEL C138W that acts as a trigger for complete protein release. The behavior of GroEL C138W was reflected closely in its in vivo characteristics, demonstrating the importance of this conformational change to the overall activity of GroEL.

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“…This r′ conformer is characterized by a elevation and clockwise twist of the apical domains (opposite direction to that seen upon ATP binding) [10]. Non-native polypeptide folding takes place within the cis ring of the R′ state of the reaction cycle, which is the longest lived (about 8–10 s) [15], and continues until ATP hydrolysis induce the R″ conformation permiting ATP binding to the opposite trans ring [16], [17]. This final rearrangement result in a conformer very similar to the r′ form (RMSd of 1.46 Å).…”

Section: Introductionmentioning

confidence: 99%

Conformational Sampling and Nucleotide-Dependent Transitions of the GroEL Subunit Probed by Unbiased Molecular Dynamics Simulations

et al. 2011

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GroEL is an ATP dependent molecular chaperone that promotes the folding of a large number of substrate proteins in E. coli. Large-scale conformational transitions occurring during the reaction cycle have been characterized from extensive crystallographic studies. However, the link between the observed conformations and the mechanisms involved in the allosteric response to ATP and the nucleotide-driven reaction cycle are not completely established. Here we describe extensive (in total long) unbiased molecular dynamics (MD) simulations that probe the response of GroEL subunits to ATP binding. We observe nucleotide dependent conformational transitions, and show with multiple 100 ns long simulations that the ligand-induced shift in the conformational populations are intrinsically coded in the structure-dynamics relationship of the protein subunit. Thus, these simulations reveal a stabilization of the equatorial domain upon nucleotide binding and a concomitant “opening” of the subunit, which reaches a conformation close to that observed in the crystal structure of the subunits within the ADP-bound oligomer. Moreover, we identify changes in a set of unique intrasubunit interactions potentially important for the conformational transition.

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Dissociation of the GroEL−GroES Asymmetric Complex Is Accelerated by Increased Cooperativity in ATP Binding to the GroEL Ring Distal to GroES

Cited by 19 publications

References 31 publications

Crystal structure of a GroEL-ADP complex in the relaxed allosteric state at 2.7 Å resolution

Crystal structure of a GroEL-ADP complex in the relaxed allosteric state at 2.7 Å resolution

GroEL-Substrate-GroES Ternary Complexes Are an Important Transient Intermediate of the Chaperonin Cycle

Conformational Sampling and Nucleotide-Dependent Transitions of the GroEL Subunit Probed by Unbiased Molecular Dynamics Simulations

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