Heat-shock protein (Hsp) 60 chaperones are almost ubiquitous and almost always essential. They can be divided on the basis of sequence homology into two broad types: group I (found in bacteria, mitochondria and chloroplasts) and group II (found in Archaea and the eukaryotic cytosol). Of the two, the group I chaperones are the better understood. Data on their structure, mechanism of action and cellular role will be briefly presented. The group II chaperones are less well studied. In eukaryotes they form large complexes with 8-fold symmetry containing eight different subunits, all of which are essential. They appear to have a major role in the folding of actin and tubulin, although they may also act on other substrates. No crystal structures are available for these complexes. The situation in the Archaea is simpler, with organisms containing between one and three genes for these chaperones. A 2.6 Å structure exists for one archaeal group II chaperone complex. Some progress has been made in defining the reaction cycle of the archaeal group II chaperones and this has shown that they have some properties distinct from the group I chaperones. To date, the in vivo role and importance of the archaeal group II Hsp60 chaperones has not been determined. We have now shown that in the halophilic archaeon Haloferax volcanii not all the genes for these proteins are essential. Further analysis of these proteins in the Archaea should be very productive in yielding more information about these important chaperones and their cellular functions.
Skip Nav Destination
Conference Article| June 01 2003
The chaperonins: perspectives from the Archaea
Publisher: Portland Press Ltd
Online ISSN: 1470-8752
Print ISSN: 0300-5127
© 2003 Biochemical Society
Biochem Soc Trans (2003) 31 (3): 681–685.
P.A. Lund, A.T. Large, G. Kapatai; The chaperonins: perspectives from the Archaea. Biochem Soc Trans 1 June 2003; 31 (3): 681–685. doi: https://doi.org/10.1042/bst0310681
Download citation file:
Don't already have an account? Register
Get Access To This Article
Buy This Article