Crystal Structure of Group II Chaperonin in the Open State

Huo, Yanwu; Hu, Zhide; Zhang, Kai; Wang, Li; Zhai, Yujia; Zhou, Qiuhong; Lander, Gabriel C.; Zhu, Jiang; He, Yang; Pang, Xiaoyun; Xü, Wei; Bartlam, Mark; Dong, Zhiyang; Sun, Fei

doi:10.1016/j.str.2010.07.009

Cited by 37 publications

(56 citation statements)

References 51 publications

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“…While group I chaperonins have 7-fold symmetric rings [29, 30], the group IIs have 8-fold and occasionally 9-fold [31–35] symmetry within their rings. Unlike GroEL, most group II chaperonins are heteromeric.…”

Section: Architecture Of Group II Chaperoninsmentioning

confidence: 99%

The Mechanism and Function of Group II Chaperonins

Lopez

Dalton

Frydman

2015

Journal of Molecular Biology

161

158

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Protein folding in the cell requires the assistance of enzymes collectively called chaperones. Among these, the chaperonins are 1 MDa ring-shaped oligomeric complexes that bind unfolded polypeptides and promote their folding within an isolated chamber in an ATP-dependent manner. Group II chaperonins, found in archaea and eukaryotes, contain a built-in lid that opens and closes over the central chamber. In eukaryotes, the chaperonin TRiC/CCT is hetero-oligomeric, consisting of two stacked rings of eight paralogous subunits each. TRiC facilitates folding of approximately 10% of the eukaryotic proteome, including many cytoskeletal components and cell cycle regulators. Folding of many cellular substrates of TRiC cannot be assisted by any other chaperone. A complete structural and mechanistic understanding of this highly conserved and essential chaperonin remains elusive. However, recent work is beginning to shed light on key aspects of chaperonin function, and how their unique properties underlie their contribution to maintaining cellular proteostasis.

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Section: Architecture Of Group II Chaperoninsmentioning

confidence: 99%

The Mechanism and Function of Group II Chaperonins

Lopez

Dalton

Frydman

2015

Journal of Molecular Biology

161

158

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“…Recent years have witnessed a great deal of structural information derived from X-ray and EM data [10,11,[72][73][74][75][76][77][78] (Fig. 1B and C).…”

Section: Overall Architecturementioning

confidence: 99%

“…4B) [73,74]. CCT is much more complex, as it has eight different apical domains; the substrate-binding region in each of these bears charged and hydrophilic residues in some subunits, whereas other subunits have hydrophobic residues [90,105].…”

Section: The Substrate Recognition Mechanismmentioning

confidence: 99%

Dynamics, flexibility, and allostery in molecular chaperonins

et al. 2015

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a b s t r a c tThe chaperonins are a family of molecular chaperones present in all three kingdoms of life. They are classified into Group I and Group II. Group I consists of the bacterial variants (GroEL) and the eukaryotic ones from mitochondria and chloroplasts (Hsp60), while Group II consists of the archaeal (thermosomes) and eukaryotic cytosolic variants (CCT or TRiC). Both groups assemble into a dual ring structure, with each ring providing a protective folding chamber for nascent and denatured proteins. Their functional cycle is powered by ATP binding and hydrolysis, which drives a series of structural rearrangements that enable encapsulation and subsequent release of the substrate protein.Chaperonins have elaborate allosteric mechanisms to regulate their functional cycle. Long-range negative cooperativity between the two rings ensures alternation of the folding chambers. Positive intra-ring cooperativity, which facilitates concerted conformational transitions within the protein subunits of one ring, has only been demonstrated for Group I chaperonins. In this review, we describe our present understanding of the underlying mechanisms and the structurefunction relationships in these complex protein systems with a particular focus on the structural dynamics, allostery, and associated conformational rearrangements.

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“…The group II chaperonin rATCpnbeta data [11], which is from Cryo-EM single particle reconstruction, is reconstructed at the the resolution of 8.4Å. It is a chaperone with a axis-based five-folded symmetry structure.…”

Section: Ratcpnbeta Datamentioning

confidence: 99%