Todd, Matthew J. and Walke, Stefan and Lorimer, George and Truscott, Kaye and Scopes, Robert K. (1995) The Single-Ring Thermoanaerobacter brockii Chaperonin 60 (Tbr-EL7) Dimerizes to Tbr-EL14.cntdot.Tbr-ES7 under Protein Folding Conditions. BIOCHEMISTRY, 34 (45). pp. 14932-14941. ISSN 0006-2960
Full text not available from this repository.Abstract
Chaperone proteins assist in the folding of some newly synthesized proteins and inhibit protein aggregation. The Thermoanaerobacter brockii chaperonin proteins (Tbr-EL and Tbr-ES) have recently been purified and characterized [Truscott, W. N., Hoj, P. B., & Scopes, R. K. (1984) Eur. J. Biochem. 222, 277-284]; Tbr-EL was a single seven-membered toroid, unlike most GroELs which exist as double toroids. Using high-resolution, gel filtration chromatography, we have resolved the purified Tbr-EL into single ringed (Tbr-EL(7)) and double ringed (Tbr-EL(14)) species. The latter contained tightly bound Tbr-ES co-chaperonin (Tbr-EL(14). Tbr-E(7)). In the presence of Mg ATP and either Escherichia coli GroES (Eco-ES) or Tbr-ES (i.e., under protein folding conditions), the isolated Tbr-EL(7) rapidly dimerized to the Tbr-EL(14). Eco-ES(7) or Tbr-EL(14)Tbr-ES(7) complexes. The doubly toroidal species thus formed contained greater than or equal to 6 molecules tightly bound ADP and one GroES(7) and are similar to the asymmetric chaperonin complex isolated from Thermus rhemzophilus [Taguchi, H., Konishi, J., Ishii, N., & Yoshida, M. (1991) J. Biol. Chem. 266, 22411-22418]. The isolated Tbr-EL(7) and Tbr-EL(14). Tbr-ES(7) hydrolyzed ATP at, similar to 2 and 1 min(-1), respectively. Addition of a molar excess of Eco-ES(7) to the isolated Tbr-EL(7) reduced the ATPase activity to 1 min(-1), consistent with the formation of Tbr-EL(14) Eco-ES(7). Eco-ES(7) failed to inhibit the Tbr-EL(14) Tbr-ES(7) complex. The isolated Tbr-EL14 . Tbr-ES(7) complex did not support the folding of Rubisco under nonpermissive conditions. Only when the complex was supplemented with additional GroES was folding of Rubisco observed; i.e., one molar equivalent of GroES was not sufficient for folding. Both Tbr-EL(7) and Tbr-EL(14). Tbr-ES(7) bound one unfolded [S-35] Rhodospirillum rubrum Rubisco per mole particle. In contrast, Eco-EL(14) bound 2 mol of protein per mole particle, consistent with each toroid having a peptide binding site. Eco-EL(14). Eco-ES(7) complex only bound one unfolded protein, thus CroES binding blocks one GroEL peptide binding site. Addition of Eco-ES(7) to a Eco-EL(14). Rubisco(2) complex did not result in the displacement of one molecule of Rubisco but in the formation of a ternary EcoEL(14). Rubisco(2) . Eco-ES(7) complex.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ESCHERICHIA-COLI GROEL; RIBULOSEBISPHOSPHATE-CARBOXYLASE; MOLECULAR CHAPERONE; ATP HYDROLYSIS; COOPERATIVITY; SURFACE; BINDING |
| Subjects: | 500 Science > 540 Chemistry & allied sciences 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biophysik und physikalische Biochemie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 17 Nov 2023 10:59 |
| Last Modified: | 17 Nov 2023 10:59 |
| URI: | https://pred.uni-regensburg.de/id/eprint/52209 |
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