Biology as Poetry: Genetics

Bacteriophage Ecology Group

E Site

Place where tRNAs, now devoid of its amino acid and polypeptide cargo, binds to the ribosome, during translation, just prior to its leaving the ribosome.

Amino acids and associated tRNAs (aminoacyl tRNAs) enter the ribosome one at a time during translation at the A site. The tRNA, now carrying a growing polypeptide, then proceeds to the P site. The associated polypeptide is then transferred to a new aminoacyl tRNA in the A site, leaving the formerly peptidyl tRNA lacking in "cargo".

The now "uncharged" tRNA then moves to the E site before leaving the ribosome. Note that these various movements occur in association with a ratcheting of the mRNA through the ribosome.

The "E" in E site stands for Exit though reasonably also may be considered to be "Empty" in the sense of the tRNA no longer carrying either amino acid or polypeptide.

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