Cryo-EM reveals an active role for aminoacyl-tRNA in the accommodation process.
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.
Valle
Mikel
M
Howard Hughes Medical Institute, Health Research, Inc., Empire State Plaza, Albany, NY 12201-0509, USA.
Sengupta
Jayati
J
Swami
Neil K
NK
Grassucci
Robert A
RA
Burkhardt
Nils
N
Nierhaus
Knud H
KH
Agrawal
Rajendra K
RK
Frank
Joachim
J
D000926:Anticodon / Q000235:genetics; D003062:Codon / Q000235:genetics; D020285:Cryoelectron Microscopy; D004926:Escherichia coli / Q000737:chemistry; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000648:ultrastructure; D006153:Guanosine Diphosphate / Q000737:chemistry; D006160:Guanosine Triphosphate / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D046911:Macromolecular Substances; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D010441:Peptide Chain Elongation, Translational; D010444:Peptide Elongation Factor Tu / Q000737:chemistry / Q000648:ultrastructure; D011487:Protein Conformation; D011728:Pyridones / Q000494:pharmacology; D012343:RNA, Transfer / Q000737:chemistry; D012346:RNA, Transfer, Amino Acyl / Q000737:chemistry / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D012360:RNA, Transfer, Phe / Q000737:chemistry / Q000378:metabolism; D012270:Ribosomes / Q000737:chemistry / Q000187:drug effects / Q000648:ultrastructure*; D013329:Structure-Activity Relationship
D000926:Anticodon; D003062:Codon; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; D011728:Pyridones; D012346:RNA, Transfer, Amino Acyl; D012360:RNA, Transfer, Phe; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D012343:RNA, Transfer; D010444:Peptide Elongation Factor Tu; C008536:mocimycin