Dimeric Procaspase-3 Unfolds via a Four-State Equilibrium Process

Bose, Kakoli; Clark, A. Clay

doi:10.1021/bi0110387

Cited by 59 publications

(157 citation statements)

References 40 publications

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“…no effect on the reversibility. These results agree with our protein folding data showing that the procaspase subunits fold reversibly at pH 7.2 when unfolding is initiated by the addition of urea (19,26).…”

Section: Resultssupporting

confidence: 92%

“…This suggests that the propeptide can bind to the inactive dimer (heterotetramer) and affect assembly of the active site following formation of the heterotetramer. This aspect of the model is consistent with our protein folding data for procaspase-3 showing that the protein undergoes isomerization following assembly of the dimer (19,26). The model shown in Fig.…”

Section: Discussionsupporting

confidence: 89%

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Reassembly of Active Caspase-3 Is Facilitated by the Propeptide

Feeney

Clark

2005

Journal of Biological Chemistry

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Changes in ionic homeostasis are early events leading up to the commitment to apoptosis. Although the direct effects of cations on caspase-3 activity have been examined, comparable studies on procaspase-3 are lacking. In addition, the effects of salts on caspase structure have not been examined. We have studied the effects of cations on the activities and conformations of caspase-3 and an uncleavable mutant of procaspase-3 that is enzymatically active. The results show that caspase-3 is more sensitive to changes in pH and ion concentrations than is the zymogen. This is due to the loss of both an intact intersubunit linker and the prodomain. The results show that, although the caspase-3 subunits reassemble to the heterotetramer, the activity return is low after the protein is incubated at or below pH 4.5 and then returned to pH 7.5. The data further show that the irreversible step in assembly results from heterotetramer rather than heterodimer dissociation and demonstrate that the active site does not form properly following reassembly. However, active-site formation is fully reversible when reassembly occurs in the presence of the prodomain, and this effect is specific for the propeptide of caspase-3. The data show that the prodomain facilitates both dimerization and active-site formation in addition to stabilizing the native structure. Overall, the results show that the prodomain acts as an intramolecular chaperone during assembly of the (pro)caspase subunits and increases the efficiency of formation of the native conformation.

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Section: Resultssupporting

confidence: 92%

Section: Discussionsupporting

confidence: 89%

Reassembly of Active Caspase-3 Is Facilitated by the Propeptide

Feeney

Clark

2005

Journal of Biological Chemistry

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“…The N 2 / N 2 * transition, dimer dissociation, and monomer unfolding are clearly reversible transitions (see Figures 1 and 5). To our knowledge, the four-state model has only been used to study the unfolding of Procaspase-3 (58). The model parameters were fitted in a simultaneous procedure to the fluorescence intensity and activity data at 50 µg/mL in Figures 3 and 5, giving the changes in Gibbs free energy reported in Table 1.…”

Section: Discussionmentioning

confidence: 99%

Reversible Equilibrium Unfolding of Triosephosphate Isomerase from Trypanosoma cruzi in Guanidinium Hydrochloride Involves Stable Dimeric and Monomeric Intermediates

et al. 2005

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The reversible guanidinium hydrochloride-induced unfolding of Trypanosoma cruzi triosephosphate isomerase (TcTIM) was characterized under equilibrium conditions. The catalytic activity was followed as a native homodimeric functional probe. Circular dichroism, intrinsic fluorescence, and size-exclusion chromatography were used as secondary, tertiary, and quaternary structural probes, respectively. The change in ANS fluorescence intensity with increasing denaturant concentrations was also determined. The results show that two stable intermediates exist in the transition from the homodimeric native enzyme to the unfolded monomers: one (N(2*)) is a slightly more expanded, non-native, and active dimer, and the other is a partially expanded monomer (M) that binds ANS. Spectroscopic and activity data were used to reach a thermodynamic characterization. The results indicate that the Gibbs free energies for the partial reactions are 4.5 (N(2) <==> N(2*)), 65.8 (N(2*) <==> 2M), and 17.8 kJ/mol (M <==> U). It appears that TcTIM monomers are more stable than those found for other TIM species (except yeast TIM), where monomer stability is only marginal. These results are compared with those for the guanidinium hydrochloride-induced denaturation of TIM from different species, where despite the functional and three-dimensional similarities, a remarkable heterogeneity exists in the unfolding pathways.

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“…The caspase dimer is formed through β-strand–β-strand interactions along β6, resulting in an extended 12-stranded β-sheet that is very stable under physiological conditions [19,30] (see Figure 1). However, depending on the type of caspase, dimerization occurs at different points in the activation process [19].…”

Section: Family C14: Caspases Metacaspases and Paracaspasesmentioning

confidence: 99%

Comparative structural analysis of the caspase family with other clan CD cysteine peptidases

McLuskey

Mottram

2015

Biochemical Journal

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Clan CD forms a structural group of cysteine peptidases, containing seven individual families and two subfamilies of structurally related enzymes. Historically, it is most notable for containing the mammalian caspases, on which the structures of the clan were founded. Interestingly, the caspase family is split into two subfamilies: the caspases, and a second subfamily containing both the paracaspases and the metacaspases. Structural data are now available for both the paracaspases and the metacaspases, allowing a comprehensive structural analysis of the entire caspase family. In addition, a relative plethora of structural data has recently become available for many of the other families in the clan, allowing both the structures and the structure–function relationships of clan CD to be fully explored. The present review compares the enzymes in the caspase subfamilies with each other, together with a comprehensive comparison of all the structural families in clan CD. This reveals a diverse group of structures with highly conserved structural elements that provide the peptidases with a variety of substrate specificities and activation mechanisms. It also reveals conserved structural elements involved in substrate binding, and potential autoinhibitory functions, throughout the clan, and confirms that the metacaspases are structurally diverse from the caspases (and paracaspases), suggesting that they should form a distinct family of clan CD peptidases.

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Dimeric Procaspase-3 Unfolds via a Four-State Equilibrium Process

Cited by 59 publications

References 40 publications

Reassembly of Active Caspase-3 Is Facilitated by the Propeptide

Reassembly of Active Caspase-3 Is Facilitated by the Propeptide

Reversible Equilibrium Unfolding of Triosephosphate Isomerase from Trypanosoma cruzi in Guanidinium Hydrochloride Involves Stable Dimeric and Monomeric Intermediates

Comparative structural analysis of the caspase family with other clan CD cysteine peptidases

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