TABLE 14.

Examples of multimeric complexes formed by some archaeal chaperonins and related proteins^a

Organism	Protein or complexb	Methodb	Detailsb	Reference(s)
Methanococcus jannaschii	sHsp	Expression in E. coli, X-ray crystallography	Oligomeric complexes, 24-mer, octahedron, Vm 22 Å3/Da	148, 149
Thermoplasma acidophilum	Thermosome	Overexpression in E. coli, crystallization, transmission EM, cryo-EM, electron tomography	Two stacked, 8-membered rings of alternating α and β subunits, α-α and β-β pairs, spherical; OD = 164 by 158; lid domain blocks central cavity; 75% of surface area of α and β are solvent exposed; ID = 54–86; chamber volumes = 325,000 Å3/assembled complex and 130,000 Å3/ring; hydrophobic, access through side windows; nonintact proteins only	65, 216, 289, 290
Methanopyrus kandleri	Thermosome	Transmission EM	Two stacked, 8-membered rings; homo-oligomers; OD = 145 by 136, ID = 43	3
Methanococcus thermolithotrophicus	MTTS	EM	Barrel-like structure; forms filaments in vitro	84
Sulfolobus sp. strain 7	Chaperonin	EM	Barrel-like structure	207
Sulfolobus shibatae	Chaperonin (TF55)	EM, circular dicroism spectroscopy, PAGE, spectrophotometry	Two stacked, 9-membered rings; 9-fold symmetry; 2 subunits; open and closed complexes; forms filaments	234, 280, 281, 307
Sulfolobus solfataricus	Chaperonin (TF55)	EM	Two stacked rings; 9-fold symmetry; 2 subunits; OD = 160 by 175, ID: = 45; crystallization	71, 154, 187
Pyrodictium occultum	Chaperonin (thermosome)	EM	Two stacked, 8-membered hetero-oligomeric rings; OD = 160 by 165, ID = 155; crystals	230, 231
Pyrodictium brockii	Chaperonin (thermosome)	EM	Barrel-like structure; OD = 160 by 155, ID = 165	231
Thermococcus strain KS-1	Chaperonin	EM	Forms homo-oligomeric rings in vitro	308

^aSee also Fig. 15. 

^bAbbreviations: V_m, volume to mass ratio; EM, electron microscopy; OD, outer diameter (angstroms); ID, inner diameter (angstroms); PAGE, polyacrylamide gel electrophoresis; MTTS, Methanococcus thermolithotrophicus chaperonin.