Scientists Revealed How Genes Translate into Proteins on Molecular Level
In the picture, the green presents the messenger RNA, the brown presents the elongation factor EF-G, and the four sequential positions of transfer RNA as it moves from right to left during translocation (dark blue, light blue, red, and gray).
Have you ever wondered how ribosome translates genetic code into proteins precisely? The question has perplexed scientists for many years. But not any more now since some researchers who also elucidated the atomic structure of the ribosome revealed the key point.
The long chains of RNA and proteins interlaced together in complicated folding form the atomic structure of ribosome. By interacting with different molecules, the conformation will differ accordingly with x-ray crystallography.
To make a new protein, the genetic instructions are first copied from the DNA sequence of a gene to a messenger RNA molecule. The ribosome then "reads" the sequence on the messenger RNA, matching each three-letter "codon" of genetic code with a specific protein building block, one of 20 amino acids. In this way, the ribosome builds a protein molecule with the exact sequence of amino acids specified by the gene. The matching of codons to amino acids is done via transfer RNA molecules, each of which carries a specific amino acid to the ribosome and lines it up with the matching codon on the messenger RNA.
How are messenger RNA and transfer RNA moved synchronously through the ribosome as the messenger RNA being translated into protein? The transfer RNAs are large macromolecules, and the ribosome has moving parts that enable it to move them through quickly and accurately at a rate of 20 per second. The translocation occurs after the bond is formed joining a new amino acid to the growing protein chain. The transfer RNA then leaves that amino acid behind and moves to the next site on the ribosome, along with a synchronous movement of the messenger RNA to bring the next codon and its associated amino acid into position for bond formation.
The finding showed the intermediate state of the process. The understanding of the structural and dynamic details of this movement could help researchers design new antibiotics by targeting the bacterial ribosomes. The finding also offered the basic mechanism for the translation of genetic code from the molecular perspective.