About Ribosomal Protein:
The ribosome is a complex molecular machine that translates the genetic code of RNA into proteins. It accomplishes this feat by breaking apart and reassembling amino acids to form peptide chains. Ribosomal proteins are a type of protein that helps in these processes, making up about one-third of all ribosomes found in our cells. This post will talk more about RPL and RPS.
Ribosomes are essential because they:
●Break down proteins into their component amino acids to build new molecules
●Synthesize the other 20 or so types of RNAs found in our cells. Ribosomes are also crucial for producing lipids and cholesterol (hence, a ribosome is sometimes called a bioreactor)
●Are central to protein synthesis
Mechanism of the Ribosome
The first thing that happens when a molecule of RNA is translated into protein by a ribosome is that it binds to an amino acid and forms an aminoacyl-tRNA. This step attaches the correct type of amino acid to the tRNA, which then binds to a specific site on one side of the large ribosomal subunit.
The tRNA then binds to the codon sequence on the mRNA (which reads from right-to-left), and a hydroxyl bond forms between its amino acid and its corresponding tRNA molecule.
Next, the other side of the RNA enters into an enzyme called peptidyl transferase, which binds to the amino acid-tRNA that has just formed and starts breaking it apart. This step creates an opening in the large subunit where a water molecule enters, pushing out one of the tRNAs.
This process is known as hydrolysis because what happens is that water breaks down or "hydrolyses" this new peptide chain. Then, the new amino acid replaces the water molecule, and the process starts again until it reaches an endpoint that signals the synthesizing of this protein.
Structure of Ribosome
A typical structure of a ribosomal protein is composed of:
Ribonucleotide reductase and the peptidyl transferase. They catalyse the formation and break down reactions in peptide chains. It also binds to mRNA and tRNA molecules during translation.
P-site (peptidyl tRNA binding site) binds the aminoacyl-tRNA molecule used in protein synthesis.
The large ribosomal subunit has a more minor and more extensive part that forms an area called the H20 tunnel, through which the water molecule passes to break down the protein.
It contains a section of mRNA and has sites where tRNA binds.
Conclusively, ribosomal proteins are responsible for the formation and breakdown of peptide chains.