3
$\begingroup$

This gif is from this page After each aminoacyl-tRNA enters the ribosome, one blue thing comes and pushes the whole tRNAs whats that? I couldn't find it anywhere.(maybe some elongation factor?) Also it seems that some thing is transporting the tRNA itself (maybe aminoacyl tRNA synthetase?)

$\endgroup$
2
$\begingroup$

The protein involved in "pushing" the tRNA and mRNA is the elongation factor EF-G. The protein involved in "transporting" the tRNA is the elongation factor EF-Tu.

Quoted from the Wikipedia articles:

EF-G:

When it binds to the ribosome A-site, EF-G causes the tRNA previously occupying that site to occupy an intermediate A/P position (bound to the A site of the small ribosomal subunit and to the P site of the large subunit), and the tRNA in the P site is shifted to a P/E hybrid state. EF-G hydrolysis of GTP causes a conformation change that forces the A/P tRNA to fully occupy the P site, the P/E tRNA to fully occupy the E site (and exit the ribosome complex), and the mRNA to shift three nucleotides down relative to the ribosome due to its association with these tRNA molecules. The GDP-bound EF-G molecule then dissociates from the complex, leaving another free A-site where the elongation cycle can start again

EF-Tu:

The tRNA anticodon domain associates with the mRNA codon domain in the ribosomal A site. If the codon-anticodon pairing is correct, EF-Tu hydrolyzes guanosine triphosphate (GTP) into guanosine diphosphate (GDP) and inorganic phosphate. This creates a conformational change in EF-Tu that causes EF-Tu to dissociate from the tRNA of the ternary complex (and therefore leave the ribosome). The aminoacyl-tRNA then fully enters the A site, where its amino acid is brought near the P site's polypeptide and the ribosome catalyzes the covalent transfer of the polypeptide onto the amino acid . The tRNA on the P site (without peptide) moves to the E site and is then released.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.