Distinct symmetry and limited peptide refolding activity of the thermosomes from the acidothermophilic archaea Acidianus tengchongensis S5(T).
Recombinant thermosomes from the Acidianus tengchongensis strain S5(T) were purified to homogeneity and assembled in vitro into homo-oligomers (rATcpnalpha or rATcpnbeta) and hetero-oligomers (rATcpnalphabeta). The symmetries of these complexes were determined by electron microscopy and image analysis. The rATcpnalpha homo-oligomer was shown to possess 8-fold symmetry while both rATcpnbeta and rATcpnalphabeta oligomers adopted 9-fold symmetry. rATcpnalphabeta oligomers were shown to contain the alpha and beta subunits in a 1:2 ratio. All of the complexes prevented the irreversible inactivation of yeast alcohol dehydrogenase at 55 degrees C and completely prevented the formation of aggregates during thermal inactivation of citrate synthase at 45 degrees C. All rATcpn complexes showed trace ATP hydrolysis activity. Furthermore, rATcpnbeta sequestered fully chemically denatured substrates (GFP and thermophilic malic dehydrogenase) in vitro without refolding them in an ATP-dependent manner. This property is similar to previously reported properties of chaperonins from Sulfolobus tokodaii and Sulfolobus acidocaldarius. These features are consistent with the slow growth rates of these species of archaea in their native environment.
Wang
Li
L
Institute of Microbiology, Chinese Academy of Sciences, Beijing, PR China.
Hu
Zhong-jun
ZJ
Luo
Yuan-ming
YM
Huo
Yan-wu
YW
Ma
Qing
Q
He
Yong-zhi
YZ
Zhang
Yu-ying
YY
Sun
Fei
F
Dong
Zhi-yang
ZY
D041541:Acidianus / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D006868:Hydrolysis; D008854:Microscopy, Electron; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D017510:Protein Folding; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016944:Sulfolobus / Q000378:metabolism; D016945:Sulfolobus acidocaldarius / Q000378:metabolism; D056405:Thermosomes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D010455:Peptides; D021122:Protein Subunits; D011994:Recombinant Proteins; D000255:Adenosine Triphosphate; D056405:Thermosomes