Protein Synthesis and Processing

Proteins are made through a process called protein synthesis. In living things, this process happens inside the cell. It is found in the cytoplasm of prokaryotes. In eukaryotes, it starts in the nucleus to make a transcript (mRNA) of the DNA’s coding region. The transcript leaves the nucleus and goes to the ribosomes, where it is turned into a protein molecule with a certain sequence of amino acids.

Protein synthesis is the process by which DNA, RNA, and different enzymes are used by cells to make proteins. It usually includes transcription, translation, and things that happen after translation, like folding, changing, and breaking down proteins.

Protein Synthesis

The creation of individual protein molecules is referred to as protein synthesis. Amino acid synthesis, transcription, translation, and post-translational events are all part of the process when it comes to biological systems. The production of amino acids from carbon sources like glucose involves a series of biochemical reactions that are referred to as the amino acid synthesis. The human body is only capable of producing a certain number of amino acids; the remaining amino acids must be supplied through the food. The processes of transcription and translation are responsible for the production of proteins inside of the cells. In a nutshell, transcription refers to the process of extracting the mRNA template from DNA. The next phase, which is translation, makes use of the template in some way. According to the genetic code, the amino acids are connected to one another in a specific order so that they can be translated. Following the completion of translation, the newly created protein is subjected to additional processing steps. These steps include proteolysis, post-translational modification, and protein folding.

Proteins are an important class of biomolecules that are essential for the survival of all forms of life. Both prokaryotes and eukaryotes are capable of producing a wide variety of proteins, which are used in a wide variety of processes and functions. While some proteins are only employed for their structural properties, others play an important role as catalysts in many metabolic processes. The processes of protein synthesis in prokaryotic and eukaryotic cells are very different from one another. For instance, the production of proteins takes place in the cytoplasm of prokaryotic cells. The nucleus is the location where the first step, transcription, takes place in eukaryotic cells. After the formation of the transcript (mRNA), the molecule travels to the cytoplasm, which is where the ribosomes are found. In this step, the mRNA is converted into a chain of amino acids.

Steps Involved in Protein Synthesis

Protein synthesis is a universal process that occurs in all living organisms. Transcription and translation are part of protein synthesis, which is a two-step process. The nucleus is where transcription occurs in eukaryotic cells. A messenger RNA (mRNA) molecule is made from a template of DNA during transcription (mRNA). The mRNA molecule exits the nucleus and enters the cytoplasm, where it is translated by a ribosome. The genetic code found in mRNA is decoded and used to produce a protein during translation. The basic dogma of molecular biology sums together these two processes: DNA RNA Protein.

• A fundamental tenet of molecular biology is that DNA inevitably leads to RNA. Genetic information is transferred from DNA to mRNA during this process. In transcription, mRNA is synthesised to match a DNA strand
• In the central dogma of molecular biology, RNA Protein, translation is the second step. mRNA is read to produce a protein by this process. The figure below shows the translation process in action. It goes to ribosomes after leaving the nucleus; these are composed of rRNA and proteins. Codons in the DNA sequence are translated into amino acids by an enzyme called the Ribonuclease (rnase) that reads the DNA sequence

Main Processes in Protein Synthesis

Transcription

A fundamental tenet of molecular biology is that DNA inevitably leads to RNA. Genetic information is transferred from DNA to mRNA during this process. The nucleus of the cell is where transcription takes place. mRNA is synthesised during transcription and is complementary to the gene’s DNA sequence. Using the DNA sequence, a gene can be discovered quickly and efficiently. The promoter, coding sequence (reading frame), and terminator are the three basic sections of a gene.

Steps of Transcription

To begin, elongation, and termination are the three stages of transcription.

• The process of transcription begins with the initiation of the process. RNA polymerase, an enzyme that binds to a region of a gene known as the promoter, is involved in this process. As a result, the enzyme can “read” a particular DNA strand’s nucleotide sequence. In order to synthesise a complementary sequence of bases, the enzyme must first synthesise a strand of mRNA. The resultant mRNA is devoid of the promoter’s sequence
• Nucleotide addition to the mRNA strand is known as elongation
• When transcription reaches its conclusion, it is said to have come to an end. RNA polymerase detaches from DNA as it transcribes the terminator. After this stage, the mRNA strand is finished and ready to use

Processing mRNA

New mRNA isn’t ready for translation in eukaryotes. Pre-mRNA must be processed further before leaving the nucleus as mature mRNA. Splicing, editing, and polyadenylation are possible. These mechanisms alter mRNA. These changes allow one gene to generate several proteins.

• Splicing removes introns from mRNA. Introns are non protein-coding regions. The remaining mRNA contains protein-coding exons. RNA-containing ribonucleoproteins are needed for splicing
• mRNA nucleotides are edited. APOB, a protein that transports blood lipids, has two versions due to editing. Editing adds an earlier stop signal to mRNA, shrinking one form
• Polyadenylation “tails” mRNA. As form the tail (adenine bases). It ends mRNA. It exports mRNA from the nucleus and shields it from enzymes

Translation

In the central dogma of molecular biology, RNA Protein, translation is the second step. mRNA is read to produce a protein by this process. It goes to ribosomes after leaving the nucleus; these are composed of rRNA and proteins. Codons in the DNA sequence are translated into amino acids by an enzyme called the Ribonuclease that reads the DNA sequence.

To fully grasp tRNA’s function, one must first gain an understanding of the structure of the molecule. Amino acid-carrying tRNA molecules each have a unique anticodon. The codon of an amino acid is complemented by an anticodon. The anticodon for the amino acid lysine is UUC, which contains the codon AAG. As a result, a tRNA molecule with the anticodon UUC would transport lysine. A UUC anticodon of tRNA is temporarily bound to any mRNA codon containing the AAG codon. tRNA loses its amino acid when linked to mRNA. A polypeptide chain is formed as the amino acids are transported to the ribosome one by one, with the aid of rRNA. Until a stop codon is found, the amino acid sequence continues to expand.

Completion

After the synthesis of a polypeptide chain, it may be subjected to further processing. As an example, it may fold because of interactions between amino acids. Another possibility is that it will bind to lipids or carbohydrates or other polypeptides. In the cytoplasm, many proteins are transported to the Golgi apparatus where they are re-engineered for the task at hand.

Conclusion

Synthesis of proteins is a fundamental activity that takes place on a continual basis inside of cells. The process results in the creation of new proteins, which are then put to use in a variety of essential bodily tasks. The procedure consists of two parts: transcription and translation, with the necessity of processing in between the two stages of transcription and translation.

First, the genetic information is copied from DNA to mRNA via the process of transcription, which involves initiation, elongation, and termination. After this step, the freshly generated mRNA exits the nucleus and binds to a ribosome in the cytoplasm. This step concludes the process. This is the point at which the translation process begins. During this stage, the genetic data is read, which causes tRNA to carry the appropriate sequence of amino acids to the ribosome, which ultimately results in the formation of a polypeptide chain. In conclusion, the polypeptide chain could be subjected to the last stage of processing in order to form the final protein.