Liu W, Kavaliauskas D, Schrader JM, Poruri K, Birkedal V, Goldman E, Jakubowski H, Mandecki W, Uhlenbeck OC, Knudsen CR, Goldman YE, Cooperman BS. Labeled EF-Tus for rapid kinetic studies of pretranslocation complex formation.
ACS Chem Biol 2014;
9:2421-31. [PMID:
25126896 PMCID:
PMC4201349 DOI:
10.1021/cb500409y]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
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The universally conserved translation
elongation factor EF-Tu delivers
aminoacyl(aa)-tRNA in the form of an aa-tRNA·EF-Tu·GTP ternary
complex (TC) to the ribosome where it binds to the cognate mRNA codon
within the ribosomal A-site, leading to formation of a pretranslocation
(PRE) complex. Here we describe preparation of QSY9 and Cy5 derivatives
of the variant E348C-EF-Tu that are functional in translation elongation.
Together with fluorophore derivatives of aa-tRNA and of ribosomal
protein L11, located within the GTPase associated center (GAC), these
labeled EF-Tus allow development of two new FRET assays that permit
the dynamics of distance changes between EF-Tu and both L11 (Tu-L11
assay) and aa-tRNA (Tu-tRNA assay) to be determined during the decoding
process. We use these assays to examine: (i) the relative rates of
EF-Tu movement away from the GAC and from aa-tRNA during decoding,
(ii) the effects of the misreading-inducing antibiotics streptomycin
and paromomycin on tRNA selection at the A-site, and (iii) how strengthening
the binding of aa-tRNA to EF-Tu affects the rate of EF-Tu movement
away from L11 on the ribosome. These FRET assays have the potential
to be adapted for high throughput screening of ribosomal antibiotics.
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