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Translation is one of the key energy consumers in cells, hence it is strictly regulated. Numerous mechanisms have evolved that control and regulate translation in eukaryotes as well as prokaryotes. Regulation of translation can impact the global rate of protein synthesis which is closely coupled to the metabolic and proliferative state of a cell.
Protein synthesis is a very similar process for both prokaryotes and eukaryotes but there are some distinct differences. [1] Protein synthesis can be divided broadly into two phases: transcription and translation. During transcription, a section of DNA encoding a protein, known as a gene, is converted into a molecule called messenger RNA (mRNA).
The termination of translation requires coordination between release factor proteins, the mRNA sequence, and ribosomes. Once a termination codon is read, release factors RF-1, RF-2, and RF-3 contribute to the hydrolysis of the growing polypeptide, which terminates the chain. Bases downstream the stop codon affect the activity of these release ...
A ribosome is made up of two subunits, a small subunit, and a large subunit. These subunits come together before the translation of mRNA into a protein to provide a location for translation to be carried out and a polypeptide to be produced. [3] The choice of amino acid type to add is determined by a messenger RNA (mRNA) molecule. Each amino ...
TFIIH is a ten-subunit protein, including both ATPase and protein kinase activities. [18] While the upstream promoter DNA is held in a fixed position by TFIID, TFIIH pulls downstream double-stranded DNA into the cleft of the polymerase, driving the separation of DNA strands and the transition of the preinitiation complex from the closed to open ...
Illustration of an activator. In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence.
These mechanisms include control over protein localization or control over whether the protein can bind DNA. [32] An example of this is the protein HSF1, which remains bound to Hsp70 in the cytosol and is only translocated into the nucleus upon cellular stress such as heat shock. Thus the genes under the control of this transcription factor ...
Electron micrographs of stained cell-free protein synthesis reactions revealed branched assemblies in which strings of ribosomes are linked to a central DNA fibre. [27] DNA isolated from bacterial cells co-sediment with ribosomes, further supporting the conclusion that transcription and translation occur together. [26]