Distinct symmetry and limited peptide refolding activity of the thermosomes from the acidothermophilic archaea Acidianus tengchongensis S5T

Wang, Li; Hu, Zhide; Luo, Yuan; Huo, Yanwu; Qian, Ma; He, Yang; Zhang, Yuying; Sun, Fenyong; Dong, Zhiyang

doi:10.1016/j.bbrc.2010.01.106

Cited by 9 publications

(13 citation statements)

References 19 publications

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“…The cpn-β is more thermally stable than cpn-α, with a T d of up to 85.1 °C (Figure 2D, left) . The hetero thermosome cpn-αβ, which is assembled from both cpn-α and cpn-β (Wang et al, 2010), has a T d of 74.4 °C, which is between that of cpn-α and cpn-β (Figure 2E, left) .…”

Section: Resultsmentioning

confidence: 99%

“…Previously, we discovered two types of thermosomes (cpn-α and cpn-β) from this archaea that share 51% sequence identity. We also showed that recombinant cpn-α predominately assembles into an eight-fold double-ring structure and that recombinant cpn-β assembles into a nine-fold structure (Wang et al, 2010). In the current study, we further investigated the assembly and thermal stability of these two thermosomes.…”

Section: Introductionmentioning

confidence: 86%

“…For N-terminus deletion mutants, the first methionine was preserved due to the needs of protein expression in E.coli . The monomers of AT cpn-α and cpn-β as well as all their variants were expressed, purified and assembled into thermosomes as previously reported (Wang et al, 2010). …”

Section: Methodsmentioning

confidence: 99%

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Flexible interwoven termini determine the thermal stability of thermosomes

et al. 2013

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Group II chaperonins, which assemble as double-ring complexes, assist in the refolding of nascent peptides or denatured proteins in an ATP-dependent manner. The molecular mechanism of group II chaperonin assembly and thermal stability is yet to be elucidated. Here, we selected the group II chaperonins (cpn-α and cpn-β), also called thermosomes, from Acidianus tengchongensis and investigated their assembly and thermal stability. We found that the binding of ATP or its analogs contributed to the successful assembly of thermosomes and enhanced their thermal stabilities. Cpn-β is more thermally stable than cpn-α, while the thermal stability of the hetero thermosome cpn-αβ is intermediate. Cryo-electron microscopy reconstructions of cpn-α and cpn-β revealed the interwoven densities of their non-conserved flexible N/C-termini around the equatorial planes. The deletion or swapping of their termini and pH-dependent thermal stability assays revealed the key role of the termini electrostatic interactions in the assembly and thermal stability of the thermosomes.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 86%

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Flexible interwoven termini determine the thermal stability of thermosomes

et al. 2013

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“…Two genes of this archaea (cpnα and cpnβ) were found to encode two types of chaperonin subunits (ATcpnα and ATcpnβ) that can assemble into thermosomes either homogenously or heterogeneously (Wang et al, 2010). Preliminary studies have shown that recombinant ATcpnα (rATcpnα) assembles into an 8-fold double ring structure, recombinant ATcpnβ (rATcpnβ) into a 9-fold structure and a combination of rATcpnα and rATcpnβ assembles into a 9-fold hetero-oligomer with 1:2 stoichiometry (Wang et al, 2010). Both of hetero-oligomer and homo-oligomer show trace ATP hydrolysis activity and limited refolding activity in vitro (Wang et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Crystal Structure of Group II Chaperonin in the Open State

Huo

Zhang

et al. 2010

Structure

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SUMMARY Thermosomes are group II chaperonins responsible for protein refolding in an ATP-dependent manner. Little is known regarding the conformational changes of thermosomes during their functional cycle due to lack of high-resolution structure in open state. Here we report the first complete crystal structure of thermosome (rATcpnβ) in open state from Acidianus tengchongensis. There is a ~30° rotation of the apical and lid domains compared to the previous closed structure. Besides, the structure reveals a conspicuous hydrophobic patch in the lid domain and residues locating in this patch are conserved across species. Both the closed and open forms of rATcpnβ were also reconstructed by electron microscopy (EM). Structural fitting revealed the detailed conformational change from open to closed state. Structural comparison as well as protease K digestion indicated only ATP binding without hydrolysis does not induce chamber closure of thermosome.

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“…This archaea contains two types of chaperonin subunits ATcpn α and ATcpn β . Prior work has shown that recombinant ATcpn α (rATcpn α ) assembles into an 8-fold double ring structure, and recombinant ATcpn β (rATcpn β ) into a 9-fold structure (Wang et al, 2010). A common feature shared by rATcpn α and rATcpn β is a characteristic double ring structure, in which each subunit contain three domains: an equatorial domain, an apical domain and an intermediate domain.…”

Section: Resultsmentioning

confidence: 99%

Single-particle reconstruction using L2-gradient flow

Xu²,

Sorzano³

et al. 2011

Journal of Structural Biology

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In this paper, we present an iterative algorithm for reconstructing a three-dimensional density function from a set of two dimensional electron microscopy images. By minimizing an energy functional consisting of a fidelity term and a regularization term, an L2-gradient flow is derived. The flow is integrated by a finite element method in the spatial direction and an explicit Euler scheme in the temporal direction. Our method compares favourably with those of the weighted back projection, Fourier method, algebraic reconstruction technique and simultaneous iterative reconstruction technique.

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Distinct symmetry and limited peptide refolding activity of the thermosomes from the acidothermophilic archaea Acidianus tengchongensis S5T

Cited by 9 publications

References 19 publications

Flexible interwoven termini determine the thermal stability of thermosomes

Flexible interwoven termini determine the thermal stability of thermosomes

Crystal Structure of Group II Chaperonin in the Open State

Single-particle reconstruction using L2-gradient flow

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