Thermosome
A thermosome is a group II chaperonin protein complex that functions in archaea. It is the homolog of eukaryotic CCT.[1] This group II chaperonin is an ATP-dependent chaperonin that is responsible for folding or refolding of incipient or denatured proteins.[2] A thermosome has two rings, each consisting of eight subunits, stacked together to form a cylindrical shape with a large cavity at the center.[2] The thermosome is also defined by its heterooligomeric nature. The complex consists of not all archaea: number varies from one to five[dubious – discuss] that alternate location within its two rings.[2]
Being a Group II chaperonin, the thermosome has a similar structure to group I chaperonins. The main difference, however, lies in the existence of a helical protrusion in the thermosome which composes of a built-in lid of the hydrophilic cavity.[2] Not only is thermosome ATP-dependent, but the mechanism in which thermosome shifts from open to close conformation is also temperature-dependent. The open conformation of the ATP-thermosome exists mainly at low temperatures.[3] Whereas, the closed conformation of the thermosome occurs when heating to physiological temperature.[3]
External links
- thermosome at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
References
- ^ Ditzel L, Löwe J; Stock D; Stetter K; Huber H; Huber R; Steinbacher S (1998). "Crystal structure of the thermosome, the archaeal chaperonin and homolog of CCT". Cell. 93 (1): 125–38. doi:10.1016/S0092-8674(00)81152-6. PMID 9546398.
- ^ a b c d Klumpp, M.; Baumeister, W. (1998-06-23). "The thermosome: archetype of group II chaperonins". FEBS Letters. 430 (1–2): 73–77. doi:10.1016/s0014-5793(98)00541-9. ISSN 0014-5793. PMID 9678597.
- ^ a b Gutsche, I.; Holzinger, J.; Rauh, N.; Baumeister, W.; May, R. P. (August 2001). "ATP-induced structural change of the thermosome is temperature-dependent". Journal of Structural Biology. 135 (2): 139–146. doi:10.1006/jsbi.2001.4373. ISSN 1047-8477. PMID 11580263.
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