Biofelsefe — Çeviri
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Biofelsefe — Çeviri


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Overview of the translation of eukaryotic messenger RNA
🔎
 
   
 

🛑 ÇEVİRİ

ÇEVİRİ

  • Çeviri RNAdan protein bireşimidir.
  • Kalıtımsal bilgi DNAnın nükleotid dizisinde bir kodda kapsanır.
  • Kodlanmış bilgi eşyazım sırasında DNAdan iletmen RNA (mRNA) olarak bilinen bir RNA biçimine aslına uygun olarak yazılır ve daha sonra amino asit zincirine çevrilir.
  • Amino asit zincirleri sarmallar, zigzaglar ve başka şekillere katlanarak proteinleri oluşturur.
  • İletmen RNAnın (mRNA) nükleotid dizisi bir tür yazılı ileti gibi düşünülebilir.
  • Bu ileti çeviri aygıtı tarafından üç nükleotid kapsayan “sözcükler”de okunur.
  • Okuma işlemi mRNAnın bir ucundan başlar ve molekül boyunca ilerler.
  • Bu üç-harfli sözcüklere kodonlar denir.
  • Her bir kodon özgül bir amino asidi temsil eder.
  • Örneğin 900 kodon 300 sözcüğe karşılık düşer ve 300 amino asitten oluşan bir zincire çevrilir.
  • Çeviri ribozomlar üzerinde yer alır.
  • Çeviri sürecinde mRNA dizisi 5' ucundan 3' ucuna bir kerede üç baz olmak üzere okunur ve büyümekte olan zincire ilgili aktarım RNAsından (tRNA) bir amino asit eklenir.
  • Çeviri ribozom bir sonlandırma kodu ile karşılaşınca durur.
  • Sonlandırma kodu normal olarak UAG, UAA ya da UGA biçimindedir.
  • Bu kodonlara karşılık olarak ribozom ile özel salma etmenleri ilişkilidir.
  • Sonlanmadan sonra yeni üretilen protein, tRNAlar, ve mRNA tümü de ayrılır ve ribozom başka bir mRNA ile etkileşime girer.
  • Herhangi bir mRNA uzunluğu boyunca birçok ribozom tarafından çevrilir.
  • Ökaryotlarda örgenlikte başka bir yere aktarılacak proteinler endoplazmik retikulumun (ER) dışına yerleşmiş ribozomlarda bireştirilir.
  • Tamamlanmış amino asit zincirleri sonra Golgi aygıtına aktarılır, oradan keseciklerin hücre membranı ile kaynaşması yoluyla hücre dışına salınır.

 



 

📹📹📹 TRANSLATION (VİDEO)

📹 Transcription and Translation — Protein Synthesis From DNA / The Organic Chemistry Tutor (VİDEO)

📹 Transcription and Translation — Protein Synthesis From DNA / The Organic Chemistry Tutor (LINK)

This biology video tutorial provides a basic introduction into transcription and translation which explains protein synthesis starting from DNA. Transcription is the process where DNA is used to create mRNA. RNA polymerase constructs DNA using the template strand or antisense strand. The other strand is called the noncoding strand or nontemplate strand. pre-mRNA is actually created first through 3 processes - initiation, elongation, and termination. After which, pre-mRNA undergoes RNA splicing where the introns are removed and the exons remain. mRNA now leaves the nucleus and enters the cytosol where it finds a ribosome which is the site where proteins are made. The nucleotide sequence found in mRNA is broken into sets of 3 forming codons which matches the anticodons found in tRNA. The transfer RNA molecule brings the amino acids needed to make the growing polypeptide chain forming a protein. The ribosome has three sites - The E site or exit site, the P site or peptidyl site, and the A site or amino acyl site where most tRNA molecules enter.

 



📹 MOLECULAR BIOLOGY OF THE GENE (VİDEO)

📹 MOLECULAR BIOLOGY OF THE GENE (LINK???)

 



📹 mRNA Translation (Basic) / DNA Learning Center (VİDEO)

📹 mRNA Translation (Basic) / DNA Learning Center (LINK)

Originally created for DNA Interactive ( http://www.dnai.org ).

TRANSCRIPT: When the RNA copy is complete, it snakes out into the outer part of the cell. Then in a dazzling display of choreography, all the components of a molecular machine lock together around the RNA to form a miniature factory called a ribosome. It translates the genetic information in the RNA into a string of amino acids that will become a protein. Special transfer molecules, the green triangles, bring each amino acid to the ribosome. The amino acids are the small red tips attached to the transfer molecules. There are different transfer molecules for each of the twenty amino acids. Each transfer molecule carries a three letter code that is matched with the RNA in the machine. Now we come to the heart of the process. Inside the ribosome, the RNA is pulled through like a tape. The code for each amino acid is read off, three letters at a time, and matched to three corresponding letters on the transfer molecules. When the right transfer molecule plugs in, the amino acid it carries is added to the growing protein chain. Again, you are watching this in real time. And after a few seconds the assembled protein starts to emerge from the ribosome. Ribosomes can make any kind of protein. It just depends what genetic message you feed in on the RNA. In this case, the end product is hemoglobin. The cells in our bone marrow churn out a hundred trillion molecules of it per second! And as a result, our muscles, brain and all the vital organs in our body receive the oxygen they need.

 



📹 mRNA Translation (Advanced) / DNA Learning Center (VİDEO)

📹 mRNA Translation (Advanced) / DNA Learning Center (LINK)

The job of the mRNA is to carry the gene's message from the DNA out of the nucleus to a ribosome for production of the particular protein that this gene codes for. Originally created for DNA Interactive ( http://www.dnai.org ).

TRANSCRIPT: The job of this mRNA is to carry the genes message from the DNA out of the nuceus to a ribosome for production of the particular protein that this gene codes for. There can be several million ribosomes in a typical eukaryotic cell these complex catalytic machines use the mrna copy of the genetic information to assemble amino acid building blokes into the three dimensional proteins that are essential for life. Lets see how it works. The ribosome is composed of one large and one small sub-unit that assemble around the messenger RNA, which then passes through the ribosome like a computer tape. The amino acid building blocks (that's the small glowing red molecules) are carried into the ribosome attached to specific transfer RNAs. That's the larger green molecules also referred to as tRNA. The small sub-unit of the ribosome positions the mRNA so that it can be read in groups of three letters known as a codon. Each codon on the mRNA matches a corresponding anti-codon on the base of a transfer RNA molecule.The larger sub-unit of the ribosome removes each amino acid and join it onto the growing protein chain. As the mRNA is ratcheted through the ribosome, the mRNA sequence is translated into an amino acid sequence. There are three locations inside the ribosome, designated the A-site, the P-site and the E-site. The addition of each amino acid is a three step cycle: First, the tRNA enters the ribosome at the A-site and is tested for a codon/anti-codon match with the mRNA. Next, provided there is a correct match, the tRNA is shifted to the P-site and the amino acid it carries is added to the end of the amino acid chain. The mRNA is also ratcheted on three nucleotides or one codon. Thirdly, the spent tRNA is moved to the E-site and then ejected from the ribosome to be recycled. As the protein synthesis proceeds, the finished chain emerges from the ribosome. It folds up into a precise shape, determined by the exact order of amino acids. Thus the Central Dogma explains how the four letter DNA code is - quite literally - turned into flesh and blood.

 



📹 Translation / Oxford Academic (Oxford University Press) (VİDEO)

📹 Translation / Oxford Academic (Oxford University Press) (LINK)

In this animation, we explore the various steps that make up the process of translation, and the molecular components involved.

 



📹 Regulation of translation / Oxford Academic (Oxford University Press) (VİDEO)

📹 Regulation of translation / Oxford Academic (Oxford University Press) (LINK)

In this animation, we consider how the process of translation is regulated in both bacteria and eukaryotes.

 



📹 Translation-Protein Synthesis (updated) / Bevelry Biology (VİDEO)

📹 Translation-Protein Synthesis (updated) / Bevelry Biology (LINK)

The process of transcription/translation is presented in an updated manner. Cleaner animations. Shorter length. Better audio.

 



📹 Translation / ndsuvirtualcell (VİDEO)

📹 Translation / ndsuvirtualcell (LINK)

NDSU Virtual Cell Animations project animation "Translation".

 



📹 Transcription and Translation / Bozeman Science (VİDEO)

📹 Transcription and Translation / Bozeman Science (LINK)

Paul Andersen explains the central dogma of biology. He explains how genes in the DNA are converted to mRNA through the process of transcription. He then explains how ribosomes use this message to convert the mRNA to a functioning protein. He also shows you how to decode a gene by converting the DNA to complementary mRNA and then to the specific amino acids in a protein.

 



📹 Transcription (DNA to mRNA) (VİDEO)

📹 Transcription (DNA to mRNA) (LINK???)

 



 

📹 Translation (mRNA to protein) / Khan Academy (VİDEO)

📹 Translation (mRNA to protein) / Khan Academy (LINK)

A deep dive into how mRNA is translated into proteins with the help of ribosomes and tRNA.

 



📹 Life Science - Protein synthesis (Translation) (VİDEO)

📹 Life Science - Protein synthesis (Translation) (LINK)

Learn about the translation process for protein synthesis.

 



 



  Translation (genetics) (B)

Translation (genetics) (B)

Translation (genetics) (B)

 
   

Translation, the synthesis of protein from RNA. Hereditary information is contained in the nucleotide sequence of DNA in a code. The coded information from DNA is copied faithfully during transcription into a form of RNA known as messenger RNA (mRNA), which is then translated into chains of amino acids. Amino acid chains are folded into helices, zigzags, and other shapes to form proteins and are sometimes associated with other amino acid chains.

The specific amounts of amino acids in a protein and their sequence determine the protein’s unique properties; for example, muscle protein and hair protein contain the same 20 amino acids, but the sequences of these amino acids in the two proteins are quite different. If the nucleotide sequence of mRNA is thought of as a written message, it can be said that this message is read by the translation apparatus in “words” of three nucleotides, starting at one end of the mRNA and proceeding along the length of the molecule. These three-letter words are called codons. Each codon stands for a specific amino acid, so if the message in mRNA is 900 nucleotides long, which corresponds to 300 codons, it will be translated into a chain of 300 amino acids.

Translation takes place on ribosomescomplex particles in the cell that contain RNA and protein. In prokaryotes (organisms that lack a nucleus) the ribosomes are loaded onto the mRNA while transcription is still ongoing. The mRNA sequence is read three bases at a time from its 5’ end toward its 3’ end, and one amino acid is added to the growing chain from its respective transfer RNA (tRNA), until the complete protein chain is assembled. Translation stops when the ribosome encounters a termination codon, normally UAG, UAA, or UGA (where U, A, and G represent the RNA bases uracil, adenine, and guanine, respectively). Special release factors associate with the ribosome in response to these codons, and the newly synthesized protein, tRNAs, and mRNA all dissociate. The ribosome then becomes available to interact with another mRNA molecule.

Any one mRNA is translated by several ribosomes along its length, each one at a different stage of translation. In eukaryotes (organisms that possess a nucleus) ribosomes that produce proteins to be used in the same cell are not associated with membranes. However, proteins that must be exported to another location in the organism are synthesized on ribosomes located on the outside of flattened membranous chambers called the endoplasmic reticulum (ER). A completed amino acid chain is extruded into the inner cavity of the ER. Subsequently, the ER transports the proteins via small vesicles to another cytoplasmic organelle called the Golgi apparatus, which in turn buds off more vesicles that eventually fuse with the cell membrane. The protein is then released from the cell.

 







 
 

🛑 ÇEVİRİ

  • Moleküler bioloji ve genetikte, çeviri DNAnın RNAya eşyazımından sonra sitoplazmada ya da ERde bulunan ribozomlarda yer alan süreçtir (bütün sürece Gen Anlatımı denir).
  • Çeviride, mRNA bir ribozomda dekode edilir ve özgül bir amino asit zinciri ya da polipeptid üretilir.
  • Polipeptid daha sonra etkin proteine katlanır.
  • Ribozom tümleyici tRNA antikodon dizilerinin mRNA kodonlarına bağlanmasını sağlar.
  • mRNA geçişini yaparken ve ribozom tarafından “okunurken,” tRNA biraraya zincirlenecek özgül amino asitleri bir polipeptide taşır.
  • Çeviri üç evre içinden ilerler:
    Başlatma: Ribozom hedef mRNA çevresinde toparlanır; ilk tRNA başlangıç kodonuna bağlanır.
    Uzatma: tRNA bir amino asidi sonraki kodona karşılık düşen tRNAya aktarır; sonra ribozom süreci sürdürmek için sonraki mRNA kodonuna ilerleyerek bir amino asit zinciri yaratır.
    Sonlandırma: Bir dur kodonuna ulaşılınca, ribozom polipeptidi salar.

 

  • Prokaryotlarda çeviri sitoplazmada olur.
  • Ökaryotlarda çeviri sitozolda ya da ERun membranı boyuna olur (eşyazım yer-değişimi).
  • Eşyazım yer-değişiminde, bütün ribozom/mRNA karmaşası kaba ERnin dış membranına bağlanır ve yeni protein bireştirilerek ERye salınır.
  • Yeni polipeptid daha sonraki kesecik aktarımı ve hücere dışına salgılama için ER içesinde depolanır ya da hemen salgılanır.
  • Bir dizi antibiotik çeviriyi engelleyerek etkide bulunur.

 



  Translation (biology) (W)

Translation (W)

Translation (biology) (W)

In molecular biology and genetics, translation is the process in which ribosomes in the cytoplasm or endoplasmic reticulum synthesize proteins after the process transcription of DNA to RNA in the cell’s nucleus. The entire process is called gene expression.

In translation, messenger RNA (mRNA) is decoded in a ribosome, outside the nucleus, to produce a specific amino acid chain, or polypeptide. The polypeptide later folds into an active protein and performs its functions in the cell. The ribosome facilitates decoding by inducing the binding of complementary tRNA anticodon sequences to mRNA codons. The tRNAs carry specific amino acids that are chained together into a polypeptide as the mRNA passes through and is "read" by the ribosome.

Translation proceeds in three phases:

  1. Initiation: The ribosome assembles around the target mRNA. The first tRNA is attached at the start codon.
  2. Elongation: The tRNA transfers an amino acid to the tRNA corresponding to the next codon. The ribosome then moves (translocates) to the next mRNA codon to continue the process, creating an amino acid chain.
  3. Termination: When a stop codon is reached, the ribosome releases the polypeptide.


In prokaryotes (bacteria), translation occurs in the cytoplasm, where the large and small subunits of the ribosome bind to the mRNA. In eukaryotes, translation occurs in the cytosol or across the membrane of the endoplasmic reticulum in a process called co-translational translocation. In co-translational translocation, the entire ribosome/mRNA complex binds to the outer membrane of the rough endoplasmic reticulum (ER) and the new protein is synthesized and released into the ER; the newly created polypeptide can be stored inside the ER for future vesicle transport and secretion outside the cell, or immediately secreted.

Many types of transcribed RNA, such as transfer RNA, ribosomal RNA, and small nuclear RNA, do not undergo translation into proteins.

A number of antibiotics act by inhibiting translation. These include anisomycin, cycloheximide, chloramphenicol, tetracycline, streptomycin, erythromycin, and puromycin. Prokaryotic ribosomes have a different structure from that of eukaryotic ribosomes, and thus antibiotics can specifically target bacterial infections without any harm to a eukaryotic host's cells.

 
 
   
 


Initiation and elongation stages of translation as seen through zooming in on the nitrogenous bases in RNA, the ribosome, the tRNA, and amino acids, with short explanations.
 
 
Basic mechanisms

Basic mechanisms

Basic mechanisms (W)

The basic process of protein production is addition of one amino acid at a time to the end of a protein. This operation is performed by a ribosome. A ribosome is made up of two subunits, a small subunit and a large subunit. these subunits come together before translation of mRNA into a protein to provide a location for translation to be carried out and a polypeptide to be produced. The choice of amino acid type to add is determined by an mRNA molecule. Each amino acid added is matched to a three nucleotide subsequence of the mRNA. For each such triplet possible, the corresponding amino acid is accepted. The successive amino acids added to the chain are matched to successive nucleotide triplets in the mRNA. In this way the sequence of nucleotides in the template mRNA chain determines the sequence of amino acids in the generated amino acid chain. Addition of an amino acid occurs at the C-terminus of the peptide and thus translation is said to be amino-to-carboxyl directed.

The mRNA carries genetic information encoded as a ribonucleotide sequence from the chromosomes to the ribosomes. The ribonucleotides are "read" by translational machinery in a sequence of nucleotide triplets called codons. Each of those triplets codes for a specific amino acid.

The ribosome molecules translate this code to a specific sequence of amino acids. The ribosome is a multisubunit structure containing rRNA and proteins. It is the "factory" where amino acids are assembled into proteins. tRNAs are small noncoding RNA chains (74–93 nucleotides) that transport amino acids to the ribosome. tRNAs have a site for amino acid attachment, and a site called an anticodon. The anticodon is an RNA triplet complementary to the mRNA triplet that codes for their cargo amino acid.

Aminoacyl tRNA synthetases (enzymes)catalyze the bonding between specific tRNAs and the amino acids that their anticodon sequences call for. The product of this reaction is an aminoacyl-tRNA. In prokaryotes, this aminoacyl-tRNA is carried to the ribosome by EF-Tu, where mRNA codons are matched through complementary base pairing to specific tRNA anticodons. Aminoacyl-tRNA synthetases that mispair tRNAs with the wrong amino acids can produce mischarged aminoacyl-tRNAs, which can result in inappropriate amino acids at the respective position in protein. This "mistranslation"of the genetic code naturally occurs at low levels in most organisms, but certain cellular environments cause an increase in permissive mRNA decoding, sometimes to the benefit of the cell.



A ribosome translating a protein that is secreted into the endoplasmic reticulum. tRNAs are colored dark blue.
 
   

The ribosome has three sites for tRNA to bind. They are the aminoacyl site (abbreviated A), the peptidyl site (abbreviated P) and the exit site (abbreviated E). With respect to the mRNA, the three sites are oriented 5’ to 3’ E-P-A, because ribosomes move toward the 3' end of mRNA. The A-site binds the incoming tRNA with the complementary codon on the mRNA. The P-site holds the tRNA with the growing polypeptide chain. The E-site holds the tRNA without its amino acid. When an aminoacyl-tRNA initially binds to its corresponding codon on the mRNA, it is in the A site. Then, a peptide bond forms between the amino acid of the tRNA in the A site and the amino acid of the charged tRNA in the P site. The growing polypeptide chain is transferred to the tRNA in the A site. Translocation occurs, moving the tRNA in the P site, now without an amino acid, to the E site; the tRNA that was in the A site, now charged with the polypeptide chain, is moved to the P site. The tRNA in the E site leaves and another aminoacyl-tRNA enters the A site to repeat the process.

After the new amino acid is added to the chain, and after the mRNA is released out of the nucleus and into the ribosome's core, the energy provided by the hydrolysis of a GTP bound to the translocase EF-G (in prokaryotes) and eEF-2 (in eukaryotes) moves the ribosome down one codon towards the 3' end. The energy required for translation of proteins is significant. For a protein containing n amino acids, the number of high-energy phosphate bonds required to translate it is 4n-1. The rate of translation varies; it is significantly higher in prokaryotic cells (up to 17–21 amino acid residues per second) than in eukaryotic cells (up to 6–9 amino acid residues per second).




The three phases of translation initiation polymerase binds to the DNA strand and moves along until the small ribosomal subunit binds to the DNA. Elongation is initiated when the large subunit attaches and termination end the process of elongation.


Even though the ribosomes are usually considered accurate and processive machines, the translation process is subject to errors that can lead either to the synthesis of erroneous proteins or to the premature abandonment of translation. The rate of error in synthesizing proteins has been estimated to be between 1/105 and 1/103 misincorporated amino acids, depending on the experimental conditions. The rate of premature translation abandonment, instead, has been estimated to be of the order of magnitude of 10−4 events per translated codon. The correct amino acid is covalently bonded to the correct transfer RNA (tRNA) by amino acyl transferases. The amino acid is joined by its carboxyl group to the 3' OH of the tRNA by an ester bond. When the tRNA has an amino acid linked to it, the tRNA is termed "charged". Initiation involves the small subunit of the ribosome binding to the 5' end of mRNA with the help of initiation factors (IF). In prokaryotes, initiation of protein synthesis involves the recognition of a purine-rich initiation sequence on the mRNA called the Shine-Delgarno sequence. The Shine-Delgarno sequence binds to a complementary pyrimidine-rich sequence on the 3' end of the 16S rRNA part of the 30S ribosomal subunit. The binding of these complementary sequences ensures that the 30S ribosomal subunit is bound to the mRNA and is aligned such that the initiation codon is placed in the 30S portion of the P-site. Once the mRNA and 30S subunit are properly bound, an initiation factor brings the initiator tRNA-amino acid complex, f-Met-tRNA, to the 30S P site. The initiation phase is completed once a 50S subunit joins the 30 subunit, forming an active 70S ribosome. Termination of the polypeptide occurs when the A site of the ribosome is occupied by a stop codon (UAA, UAG, or UGA) on the mRNA. tRNA usually cannot recognize or bind to stop codons. Instead, the stop codon induces the binding of a release factor protein. (RF1 & RF2) that prompts the disassembly of the entire ribosome/mRNA complex by the hydrolysis of the polypeptide chain from the peptidyl transferase center of the ribosome Drugs or special sequence motifs on the mRNA can change the ribosomal structure so that near-cognate tRNAs are bound to the stop codon instead of the release factors. In such cases of 'translational readthrough', translation continues until the ribosome encounters the next stop codon.


Tertiary structure of tRNA. CCA tail in yellow, Acceptor stem in purple, Variable loop in orange, D arm in red, Anticodon arm in blue with Anticodon in black, T arm in green.
 
   

The process of translation is highly regulated in both eukaryotic and prokaryotic organisms. Regulation of translation can impact the global rate of protein synthesis which is closely coupled to the metabolic and proliferative state of a cell. In addition, recent work has revealed that genetic differences and their subsequent expression as mRNAs can also impact translation rate in an RNA-specific manner.

 



 
Mathematical modeling of translation

Mathematical modeling of translation

Mathematical modeling of translation (W)

The transcription-translation process description, mentioning only the most basic ”elementary” processes, consists of:

  1. production of mRNA molecules (including splicing),
  2. initiation of these molecules with help of initiation factors (e.g., the initiation can include the circularization step though it is not universally required),
  3. initiation of translation, recruiting the small ribosomal subunit,
  4. assembly of full ribosomes,
  5. elongation, i.e. movement of ribosomes along mRNA with production of protein,
  6. termination of translation,
  7. degradation of mRNA molecules,
  8. degradation of proteins.

 

The process of protein synthesis and translation is a subject of mathematical modeling for a long time starting from the first detailed kinetic models such as or others taking into account stochastic aspects of translation and using computer simulations. Many chemical kinetics-based models of protein synthesis have been developed and analyzed in the last four decades. Beyond chemical kinetics, various modeling formalisms such as Totally Asymmetric Simple Exclusion Process (TASEP), Probabilistic Boolean Networks (PBN), Petri Nets and max-plus algebra have been applied to model the detailed kinetics of protein synthesis or some of its stages. A basic model of protein synthesis that took into account all eight 'elementary' processes has been developed, following the paradigm that "useful models are simple and extendable". The simplest model M0 is represented by the reaction kinetic mechanism (Figure M0). It was generalised to include 40S, 60S and initiation factors (IF) binding (Figure M1'). It was extended further to include effect of microRNA on protein synthesis. Most of models in this hierarchy can be solved analytically. These solutions were used to extract 'kinetic signatures' of different specific mechanisms of synthesis regulation.

 


Figure M0. Basic and the simplest model M0 of protein synthesis. Here, *M – amount of mRNA with translation initiation site not occupied by assembling ribosome, *F – amount of mRNA with translation initiation site occupied by assembling ribosome, *R – amount of ribosomes sitting on mRNA synthesizing proteins, *P – amount of synthesized proteins.
 


Figure M1'. The extended model of protein synthesis M1 with explicit presentation of 40S, 60S and initiation factors (IF) binding.

 



 
Genetic code

Genetic code

Genetic code (W)

Main article: Genetic code

Whereas other aspects such as the 3D structure, called tertiary structure, of protein can only be predicted using sophisticated algorithms, the amino acid sequence, called primary structure, can be determined solely from the nucleic acid sequence with the aid of a translation table.

This approach may not give the correct amino acid composition of the protein, in particular if unconventional amino acids such as selenocysteine are incorporated into the protein, which is coded for by a conventional stop codon in combination with a downstream hairpin (SElenoCysteine Insertion Sequence, or SECIS).

There are many computer programs capable of translating a DNA/RNA sequence into a protein sequence. Normally this is performed using the Standard Genetic Code, however, few programs can handle all the "special" cases, such as the use of the alternative initiation codons. For instance, the rare alternative start codon CTG codes for Methionine when used as a start codon, and for Leucine in all other positions.

Example: Condensed translation table for the Standard Genetic Code (from the NCBI Taxonomy webpage).

AAs    = FFLLSSSSYY**CC*WLLLLPPPPHHQQRRRRIIIMTTTTNNKKSSRRVVVVAAAADDEEGGGG   
Starts = ---M---------------M---------------M----------------------------
Base1 = TTTTTTTTTTTTTTTTCCCCCCCCCCCCCCCCAAAAAAAAAAAAAAAAGGGGGGGGGGGGGGGG
Base2 = TTTTCCCCAAAAGGGGTTTTCCCCAAAAGGGGTTTTCCCCAAAAGGGGTTTTCCCCAAAAGGGG
Base3 = TCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAG

The "Starts" row indicate three start codons, UUG, CUG, and the very common AUG. It also indicates the first amino acid residue when interpreted as a start: in this case it is all methionine.

 



 
See also

 







 
 

 


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