Introduction
The formation of proteins takes place when amino acids link together, where each protein has a unique amino acid sequence and characteristic. To get an idea for the diversity of the proteins that can be formed with the use of 20 dissimilar amino acids, consider that the amount of several combinations possible with 20 amino acids is 20n. Here, ‘n’ will be the number of amino acids in the chain. It gets obvious that even a dipeptide formed with 2 amino acids linked together gives 202 = 400 dissimilar combinations.
Definition
The proteins are considered as the workhorses of the cell. Virtually, all that goes inside the cells happens because of the actions of the proteins. Among various other elements, the enzymes of the protein catalyze the huge majority of cellular reactions, mediate signaling, and provide structure to both cells and multicellular organisms. Moreover, these exert control on the expression of genes. Life cannot survive without proteins and due to their varied structures, the versatility of proteins occurs.
Protein Synthesis
The occurrence of synthesis of the proteins takes place in the ribosomes and continues by the joining of the carboxyl terminus of the first amino acid and the amino terminus of the next amino acid. In addition, the end of the protein having a free α-amino group is known as the N-terminus and the other end is termed as the C-terminus, meanwhile, it has the only free α-carboxyl group.
Intermediate Filament
The intermediate filaments are present in the cells of vertebrates and multiple invertebrates. Moreover, these are the cytoskeletal structural components. The homologous intermediate filaments protein is found in the cephalochordata Branchiostoma, an invertebrate.
Intermediate Filaments Function
The structure of the proteins that make intermediate filaments was initially predicted by computerized analysis of the sequence of amino acids of human keratin derived from artificial cDNAs. This is what we can consider as the intermediate filaments function.
Primary Structure of Protein
It is the ultimate determinant of the complete conformation of a protein. The primary structure of proteins, of any kind, has been derived as a result of years of mutation and selection. The primary structure of proteins is directed by the DNA coding sequence for it in the genome.
The areas of DNA that specify the proteins are called the coding regions as well as genes. In addition, the sequence of the amino acids in proteins is directly specified by the base sequences of these regions. Moreover, it occurs with a one-to-one correspondence amid the codons, codons are basically the group of 3 consecutive bases in the DNA and the amino acids in the protein which is encoded.
Secondary Structure of Protein
As the progression of protein synthesis takes place, the interactions start amid the amino acids which are nearby and this gives rise to the local patterns also known as the secondary structure. These secondary structures involve the popularly known β-strands and α- helix. Robert Corey, Herman Branson and Linus Pauling predicted both these structures in 1951.
Tertiary Structure of Protein
The proteins are differentiated from each other with the help of a sequence of the amino acids which comprise them. The amino acids series regulates the shape of the protein. Moreover, the sequence also defines random coils and turns that have a vital role in the protein folding process.
Quaternary Structure of Protein
The quaternary structure of protein has a nature that is demonstrated by the hemoglobin’s structure. Each molecule of the hemoglobin of a person has four peptide chains that consist of 2 α-chains and 2 β-chains since it is a tetramer. These four subunits are connected with each other with the help of the hydrophobic interaction and the hydrogen bonds. Because of their close link, the hemoglobin tetramer is known as a molecule. In various other types of proteins, the subunits are linked to each other through covalent bonds, also known as disulphide bridges.
Quinary Structure of Protein
Quinary structure is the fifth level of protein complexity.They show marked plasticity and inequivalence in the juxtaposition of constituent molecules.Quinary structure of protein results from the adaptations present on the protein structure.
The Isolation and Determination of Proteins
The materials of the animals commonly have huge amounts of protein as well as lipids, and small amounts of carbohydrate; in plants, dry matter bulk is mostly carbohydrate. When it becomes necessary to determine the quantity of protein in a mixture of foodstuffs of the animals, conversion of a sample to ammonium salts takes place by the process of boiling in sulphuric acid and an appropriate inorganic catalyst like copper sulfate. The procedure is based on the assumption that proteins have 16 percent of nitrogen, and that protein nitrogen is absent in tiny amounts.
The assumption mentioned above is justified for the majority of tissues from the higher animals but not in the case of crustaceans and insects, which have a considerable amount of body nitrogen in the form of a carbohydrate known as chitin. In many types of plants, a large number of no protein nitrogen is found. In these cases, the formation of the precise quantitative analysis takes place after the separation of the proteins from other biological compounds.
Conclusion
The proteins are made as chains of amino acids, later, which turn into unique and exclusive 3D shapes. Moreover, while bonding within the molecules of the protein, assists in stabilizing their structure as well as the final folded forms of proteins are properly adapted for their respective functions.