The C-terminal helix of Pseudomonas aeruginosa elongation factor Ts tunes EFT-Tu dynamics to modulate nucleotide exchange

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De Laurentiis, Evelina I.
Mercier, Evan
Wieden, Hans-Joachim
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American Society for Biochemistry and Molecular Biology
Little is known about the conservation of critical kinetic parameters and the mechanistic strategies of elongation factor (EF) Ts-catalyzed nucleotide exchange in EF-Tu in bacteria and particularly in clinically relevant pathogens. EF-Tu from the clinically relevant pathogen Pseudomonas aeruginosa shares over 84% sequence identity with the corresponding elongation factor from Escherichia coli. Interestingly, the functionally closely linked EF-Ts only shares 55% sequence identity. To identify any differences in the nucleotide binding properties, as well as in the EF-Ts-mediated nucleotide exchange reaction, we performed a comparative rapid kinetics and mutagenesis analysis of the nucleotide exchange mechanism for both the E. coli and P. aeruginosa systems, identifying helix 13 of EF-Ts as a previously unnoticed regulatory element in the nucleotide exchange mechanism with species-specific elements. Our findings support the base side-first entry of the nucleotide into the binding pocket of the EF-Tu·EF-Ts binary complex, followed by displacement of helix 13 and rapid binding of the phosphate side of the nucleotide, ultimately leading to the release of EF-Ts.
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GTPase , Molecular dynamics , Pre-steady-state kinetics , Pseudomonas aeruginosa (P. aeruginosa) , Translation elongation factor , Elongation factor Ts , Elongation factor Tu , Catalytic mechanism , Nucleotide binding , Nucleotide exchange
De Laurentiis, E. I., Mercier, E., & Wieden, H.-J. (2016). The C-terminal helix of Pseudomonas aeruginosa elongation factor Ts tunes EF-Tu dynamics to modulate nucleotide exchange. Journal of Biological Chemistry, 291(44), 23136-023148. doi:10.1074/jbc.M116.740381