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Figure 4.
Figure 4: Model of the role of eEF3 in the fungal elongation
cycle. a, The post-state ribosome with a locked E-site tRNA
owing to the L1 stalk in the 'in' position and the conformation
of the 40S head (Post, locked E). b, Hypothetical initial
interaction of eEF3 in the open tandem or intermediate
conformation (Post*, locked E). c, Ribosome interaction triggers
the ATP-dependent closed tandem formation and high-affinity
ribosome binding by eEF3, as observed by cryo-EM (Post*). A
conformational switch of the chromodomain stabilizes the L1
stalk in the 'out' position (unlocked E). d, ATP hydrolysis of
the closed tandem results in the dissociation of eEF3, E-site
opening, and unlocking of the 40S head (Post). Now,
eEF1A–GTP–aminoacyl-tRNA can bind and the E-site deacyl-tRNA
is released. ATP hydrolysis by eEF3, tRNA release, and A-site
loading by eEF1A may take place as a joint event. aatRNA,
aminoacyl-tRNA. RSR, ratchet-like subunit rearrangement.
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