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  • The EMBO Journal (2002) 21, 3557 - 3567
  • doi:10.1093/emboj/cdf326

Cryo-EM reveals an active role for aminoacyl-tRNA in the accommodation process

Mikel Valle1, Jayati Sengupta2, Neil K. Swami3, Robert A. Grassucci1, Nils Burkhardt4, Knud H. Nierhaus4, Rajendra K. Agrawal2,5 and Joachim Frank1,5

  1. Howard Hughes Medical Institute, Health Research, Inc., at the New York State Department of Health, Empire State Plaza, Albany, NY 12201-0509, USA
  2. Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201-0509, USA
  3. Columbia High School, 962 Luther Road, East Greenbush, NY 12061, USA
  4. Max-Planck-Institut für Molekulare Genetik, Ihnestrasse 73, D-14195 Berlin, Germany
  5. Department of Biomedical Sciences, State University of New York at Albany, Empire State Plaza, Albany, NY 12201-0509, USA

Correspondence to:

Joachim Frank, E-mail: joachim@wadsworth.org

Received 25 February 2002; Accepted 3 May 2002; Revised 16 April 2002

During the elongation cycle of protein biosynthesis, the specific amino acid coded for by the mRNA is delivered by a complex that is comprised of the cognate aminoacyl-tRNA, elongation factor Tu and GTP. As this ternary complex binds to the ribosome, the anticodon end of the tRNA reaches the decoding center in the 30S subunit. Here we present the cryo- electron microscopy (EM) study of an Escherichia coli 70S ribosome-bound ternary complex stalled with an antibiotic, kirromycin. In the cryo-EM map the anticodon arm of the tRNA presents a new conformation that appears to facilitate the initial codon–anticodon interaction. Furthermore, the elbow region of the tRNA is seen to contact the GTPase-associated center on the 50S subunit of the ribosome, suggesting an active role of the tRNA in the transmission of the signal prompting the GTP hydrolysis upon codon recognition.

  • Keywords:

    • decoding,
    • electron microscopy,
    • elongation factor Tu,
    • ribosome,
    • tRNA