Protein Synthesis Summary Protein synthesis is one of the most fundamental biological processes by which individual cells build their specific proteins. Within the process are involved both DNA (deoxyribonucleic acid) and different in their function ribonucleic acids (RNA). The process is initiated in the cell’s nucleus, where specific enzymes unwind the needed section of DNA, which makes the DNA in this region accessible and a RNA copy can be made. This RNA molecule then moves from the nucleus to the cell cytoplasm, where the actual the process of protein synthesis take place. What is protein synthesis – The details! All cells function through their proteins. Protein function is defined by their molecular function , localization within cell and involvement in a particular biological process. All components of protein function are defined by the exact composition, structure and conformation of the proteins, which is encrypted within the DNA region (called locus) encoding that protein. With the process of protein synthesis biological cells generate new proteins, which on the other hand is balanced by the loss of cellular proteins via degradation or export. Within the process called Transcription, the information encoded in the DNA is copied to a RNA molecule as one strand of the DNA double helix is used as a template. The RNA molecule is sent to the cytoplasm, which helps to bring all components required for the actual protein synthesis together – amino acids, transport RNAs, ribosomes, etc. In the cytoplasm the protein polymers are actually “synthesized” through chemical reactions – that is why the process is known as “protein synthesis” or even more precisely – “protein biosynthesis”. The RNA copy of the protein genetic information encoded in DNA molecule is produced in the nucleus and it is called messenger RNA (mRNA). Each mRNA encodes the information for a single protein and is much smaller in size compared to the DNA molecule. This makes possible for mRNA molecules to exit the nucleus through tiny openings called nuclear pores. Once it exits the nucleus and enters the cytoplasm, the mRNA could interact with a cellular structure known as a ribosome, which serves as the cell’s assembler within the process of protein synthesis. The ribosome consists of proteins and ribosome RNA molecules (rRNA), which are organized in two subunits. The mRNA initially binds to just one of the ribosome sub-units. When the mRNA interacts with the big ribosome sub-unit, this triggers the approach of another RNA molecule, called transfer RNA (tRNA). The tRNA molecule possess a specific sequence of 3-bases (anti-codon), which hast to complement a corresponding sequence (codon) within the mRNA sequence. When it finds it, it attaches to the mRNA, as the other end of the tRNA is “loaded” with an amino acid. At this point arrives the other sub-unit of the ribosome and a complete structure is formed. The first tRNA binds to a so called “start codon”, which is one and the same for all proteins. As the complete ribosome structure is formed, another tRNA molecule approaches. The next tRNA differ from the first one and is carrying another amino acid. Again, the tRNA must have an anti-codon that matches complementary the second codon of the mRNA. The two amino acids carried by the first two tRNAs are bind together with help from the ribosome and using cellular energy in the form of adenosine triphosphate (ATP). The above steps repeats until there are uncoupled codon sequences on the mRNA – thus the chain of amino acids grows longer. Once the sequence of amino acids is successfully assembled in a protein, the two ribosome sub-units separate from each other, to be joined again for later use. The actual sequence of amino acids forms the so called primary structure of the proteins. Depending on the exact composition and order of the amino acids in the protein sequence, the chain folds into a three-dimensional shape. When this happens the protein is complete. The process of protein synthesis takes place in multiple ribosomes simultaneous and all throughout the cell cytoplasm. A living cell can synthesize hundreds of different proteins every single second. Protein Synthesis Described With Images Latest Resarch Articles For Protein Synthesis In vitro and in vivo single-molecule fluorescence imaging of ribosome-catalyzed protein synthesis. Related Articles In vitro and in vivo single-molecule fluorescence imaging of ribosome-catalyzed protein synthesis. Curr Opin Chem Biol. 2011 Dec;15(6):853-63 Authors: Perez CE, Gonzalez RL Abstract Combined with the availability of highly purified, fluorescently labeled in vitro translation systems, the advent of single-molecule fluorescence imaging has ush […] Termination of protein synthesis in mammalian mitochondria. Related Articles Termination of protein synthesis in mammalian mitochondria. J Biol Chem. 2011 Oct 7;286(40):34479-85 Authors: Chrzanowska-Lightowlers ZM, Pajak A, Lightowlers RN Abstract All mechanisms of protein synthesis can be considered in four stages: initiation, elongation, termination, and ribosome recycling. Remarkable progress has been made in unde […] Using transgenic modulation of protein synthesis and accumulation to probe protein signaling networks in Arabidopsis thaliana. Related Articles Using transgenic modulation of protein synthesis and accumulation to probe protein signaling networks in Arabidopsis thaliana. Plant Signal Behav. 2011 Sep;6(9):1312-21 Authors: Warnasooriya SN, Montgomery BL Abstract Deployment of new model species in the plant biology community requires the development and/or improvement of numerous geneti […] Exercise, amino acids, and aging in the control of human muscle protein synthesis. Related Articles Exercise, amino acids, and aging in the control of human muscle protein synthesis. Med Sci Sports Exerc. 2011 Dec;43(12):2249-58 Authors: Walker DK, Dickinson JM, Timmerman KL, Drummond MJ, Reidy PT, Fry CS, Gundermann DM, Rasmussen BB Abstract In this review, we discuss recent research in the field of human skeletal muscle protein metabolis […] Regulation of protein synthesis by amino acids in muscle of neonates. Related Articles Regulation of protein synthesis by amino acids in muscle of neonates. Front Biosci. 2011;16:1445-60 Authors: Suryawan A, Davis TA Abstract The marked increase in skeletal muscle mass during the neonatal period is largely due to a high rate of postprandial protein synthesis that is modulated by an enhanced sensitivity to insulin and amino aci […] Subcellular communication through RNA transport and localized protein synthesis. Related Articles Subcellular communication through RNA transport and localized protein synthesis. Traffic. 2010 Dec;11(12):1498-505 Authors: Donnelly CJ, Fainzilber M, Twiss JL Abstract Interest in the mechanisms of subcellular localization of mRNAs and the effects of localized translation has increased over the last decade. Polarized eukaryotic cells transp […] Triennial Growth Symposium: leucine acts as a nutrient signal to stimulate protein synthesis in neonatal pigs. Related Articles Triennial Growth Symposium: leucine acts as a nutrient signal to stimulate protein synthesis in neonatal pigs. J Anim Sci. 2011 Jul;89(7):2004-16 Authors: Suryawan A, Orellana RA, Fiorotto ML, Davis TA Abstract The postprandial increases in AA and insulin independently stimulate protein synthesis in skeletal muscle of piglets. Leucine is an […] Regulation of protein synthesis and the role of eIF3 in cancer. Related Articles Regulation of protein synthesis and the role of eIF3 in cancer. Braz J Med Biol Res. 2010 Oct;43(10):920-30 Authors: Hershey JW Abstract Maintenance of cell homeostasis and regulation of cell proliferation depend importantly on regulating the process of protein synthesis. Many disease states arise when disregulation of protein synthesis occu […] Terminating human mitochondrial protein synthesis: a shift in our thinking. Related Articles Terminating human mitochondrial protein synthesis: a shift in our thinking. RNA Biol. 2010 May-Jun;7(3):282-6 Authors: Lightowlers RN, Chrzanowska-Lightowlers ZM Abstract Until recently, human mitochondria were regarded as unusual as they appeared to employ four stop codons to terminate translation. In addition to the UAA/UAG of the universa […] The role of milk- and soy-based protein in support of muscle protein synthesis and muscle protein accretion in young and elderly persons. Related Articles The role of milk- and soy-based protein in support of muscle protein synthesis and muscle protein accretion in young and elderly persons. J Am Coll Nutr. 2009 Aug;28(4):343-54 Authors: Phillips SM, Tang JE, Moore DR Abstract The balance between muscle protein synthesis (MPS) and muscle protein breakdown (MPB) is dependent on protein consumpt […]
Posted on: Tue, 04 Jun 2013 13:54:53 +0000
Trending Topics
Recently Viewed Topics
© 2015