What is posttranslation modification?

Posttranslation modification (PTM) is a process in protein biosynthesis that occurs after translation of protein from ribonucleic acid (RNA). The translation process involves creating an amino acid chain that corresponds to the RNA template. Once this string has been created, the protein has been synthesized, but must often be subjected to further changes before it becomes fully functional. These changes are known as posttranslation modifications and include three -dimensional shaping, formation of disulphide bridges, phosphorylation or adding other molecules. This process often occurs directly after translation and is powered by hydrophobic interactions. Because the intracellular environment is aqueous, hydrophobic groups that repel the cluster of water to the center of the Away protein from the water and the creation of an energy -stable form. Other proteins, known as chaperonins, can also help the newly created proteins fold into their correct shape.

disulfIdent bridges and reactions of proteolytic cleavage are other posttranslation structural changes that may occur in proteins. If the protein contains two remnants of cysteine ​​amino acid, it can create a covalent link between them if they are properly aligned, thus changing the conformation of the protein. Similarly, some structural changes occur due to proteolytic cleavage, in which the enzyme cuts off a piece of protein after its folding. An example of this process is a protein insulin, which remains in inactive precursor form until it is subjected to proteolytic cleavage to form an active molecule.

Adding functional groups such as phosphate groups, sulphate groups, achyl groups or methyl groups is also common posttranslation modification. These groups can either activate the protein, inhibit it, or signal it to move elsewhere in the cell. For example, many enzymes pass between active and inactive states depending on whether they were or not phosphorylated.

Ubricvitation is another form of post -translation modification used by cells to indicate proteins. The process involves adding ubiquitin, small signaling protein, to an active protein that targets degradation. Although ubiquitin may sometimes also act as a signaling molecule, it is generally used to adjust the active proteins that the cell is trying to degrade. In this way, the cell is able to control the levels of different enzymes and other proteins according to changes in the environment.