Translation

ID #2409

I'm a little confused with the charging process. Are the tRNA's just floating around (in the cytoplasm?) and the aminoacyl tRNA synthetases will check the anticodon, and attach the proper amino acid? then these 'charged' tRNA's will base pair to the mRNA and form a long chain of amino acids linked to the mRNA by the tRNA?


Yes, tRNAs are found in the cytoplasm, where they "float" around until they are properly charged by an aminoacyl tRNA synthetase. You are correct that the aminoacyl tRNA synthetase checks the anticodon and then adds the correct amino acid. 
The charged tRNA does use base-pairing to match its anticodon to the correct codon on the mRNA. 
However, the amino acids are not directly linked to the mRNA, and the base pairing between the codon and anticodon is temporary. 
During translation, the peptidyl transferase portion of the ribosome will break the covalent bond between the charged tRNA and its amino acid. That energy will be used to form the peptide bond between the amino acids. If this is the second amino acid in the protein, this would leave both amino acids attached to the tRNA in the A site. 
This is when elongation factor G comes in for translocation. The translocation moves the ribosome on the mRNA. As a result, the tRNA in the P site (now with no amino acid attached) is now at the E site, where it will be peeled off and float away. 
The tRNA (with 2 amino acids) that was in the A site is now in the P site. And there is space in the A site for the next charged tRNA to come in. 

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