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https://hdl.handle.net/1959.11/76
Title: | Oligomeric State and Mode of Self-Association of Thermotoga maritima Ribosomal Stalk Protein L12 in Solution | Contributor(s): | Moens, P (author) ; Wahl, MC (author); Jameson, DM (author) | Publication Date: | 2005 | DOI: | 10.1021/bi048015n | Handle Link: | https://hdl.handle.net/1959.11/76 | Abstract: | The "stalk" of the prokaryotic 50S ribosomal subunit is comprised of four copies of the protein L7/L12. In Escherichia coli, L7/L12 is a dimeric protein at micromolar concentrations, which is able to undergo rapid subunit exchange. A recent structural study indicated a tetrameric arrangement of the L12 proteins isolated from Thermotoga maritima, in which the proteins engaged in two different dimerization modes. In one mode, the two monomers of L12 form a tight symmetric and parallel dimer held together by a four-helix bundle, which encompasses the hinge region between the N- and C-terminal domains. In the other mode, the two monomers bind through their N-terminal region in an antiparallel configuration, in which one monomer comprises an -helical hinge and the other monomer adopts an elongated shape with an unfolded hinge region. Presently, it is unclear which dimer contact prevails in solution and on the ribosome. Using cysteine mutants of T. maritima labeled with fluorescent probes, we investigated the mode of interactions between L12 subunits. Data from Förster resonance energy transfer experiments support a dimerization of L12 in solution, in which two monomers bind through their N-terminal region in an antiparallel configuration. We also demonstrate that the rate of subunit exchange in T. maritima L12 is significantly slower at 25 C than that in the E. coli system. The exchange rate increases with increasing temperature and approaches the one observed for the E. coli system at 50 C. Possible factors responsible for this difference are discussed. | Publication Type: | Journal Article | Source of Publication: | Biochemistry, 44(9), p. 3298-3305 | Publisher: | American Chemical Society | Place of Publication: | United States of America | ISSN: | 1520-4995 0006-2960 |
Fields of Research (FoR) 2008: | 029901 Biological Physics | Peer Reviewed: | Yes | HERDC Category Description: | C1 Refereed Article in a Scholarly Journal |
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Appears in Collections: | Journal Article School of Science and Technology |
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