An update on the biophysical character of the human eukaryotic elongation factor 1 beta: Perspectives from interaction with elongation factor 1 gamma.

Autor: Achilonu I; Protein Structure-Function Research Unit, School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Johannesburg, South Africa., Elebo N; Protein Structure-Function Research Unit, School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Johannesburg, South Africa., Hlabano B; Protein Structure-Function Research Unit, School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Johannesburg, South Africa., Owen GR; HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa., Papathanasopoulos M; HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa., Dirr HW; Protein Structure-Function Research Unit, School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Johannesburg, South Africa.
Jazyk: angličtina
Zdroj: Journal of molecular recognition : JMR [J Mol Recognit] 2018 Jul; Vol. 31 (7), pp. e2708. Date of Electronic Publication: 2018 Mar 23.
DOI: 10.1002/jmr.2708
Abstrakt: The β-subunit of the human eukaryotic elongation factor 1 complex (heEF1β) plays a central role in the elongation step in eukaryotic protein biosynthesis, which essentially involves interaction with the α- and γ-subunits (eEF1γ). To biophysically characterize heEF1β, we constructed 3 Escherichia coli expression vector systems for recombinant expression of the full length (FL-heEF1β), N-terminus (NT-heEF1β), and the C-terminus (CT-heEF1β) regions of the protein. Our results suggest that heEF1β is predominantly alpha-helical and possesses an accessible hydrophobic cavity in the CT-heEF1β. Both FL-heEF1β and NT-heEF1β form dimers of size 62 and 30 kDa, respectively, but the CT-heEF1β is monomeric. FL-heEF1β interacts with the N-terminus glutathione transferase-like domain of heEF1γ (NT-heEF1γ) to form a 195-kDa complex or a 230-kDa complex in the presence of oxidized glutathione. On the other hand, NT-heEF1β forms a 170-kDa complex with NT-heEF1γ and a high molecular weight aggregate of size greater than 670 kDa. Surface plasmon resonance analysis confirmed that (by fitting the Langmuir 1:1 model) FL-heEF1β associated with monomeric or dimeric NT-heEF1γ at a rapid rate and slowly dissociated, suggesting strong functional affinity (K D  = 9.6 nM for monomeric or 11.3 nM for dimeric NT-heEF1γ). We postulate that the N-terminus region of heEF1β may be responsible for its dimerization and the C-terminus region of heEF1β modulates the formation of an ordered heEF1β-γ oligomer, a structure that may be essential in the elongation step of eukaryotic protein biosynthesis.
(Copyright © 2018 John Wiley & Sons, Ltd.)
Databáze: MEDLINE
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