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Kozak Consensus Sequence
The Kozak consensus sequence (Kozak consensus or Kozak sequence) is a Nucleic acid sequence, nucleic acid motif that functions as the protein Translation (biology), translation initiation site in most eukaryotic Messenger RNA, mRNA transcripts. Regarded as the optimum sequence for initiating translation in eukaryotes, the sequence is an integral aspect of protein regulation and overall cellular health as well as having implications in human disease. It ensures that a protein is correctly translated from the genetic message, mediating ribosome assembly and translation initiation. A wrong start site can result in non-functional proteins. As it has become more studied, expansions of the nucleotide sequence, bases of importance, and notable exceptions have arisen. The sequence was named after the scientist who discovered it, Marilyn Kozak. Kozak discovered the sequence through a detailed analysis of DNA genomic sequences. The Kozak sequence is not to be confused with the ribosomal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Nucleic Acid Sequence
A nucleic acid sequence is a succession of Nucleobase, bases within the nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. This succession is denoted by a series of a set of five different letters that indicate the order of the nucleotides. By convention, sequences are usually presented from the Directionality (molecular biology), 5' end to the 3' end. For DNA, with its double helix, there are two possible directions for the notated sequence; of these two, the Sense (molecular biology), sense strand is used. Because nucleic acids are normally linear (unbranched) polymers, specifying the sequence is equivalent to defining the covalent structure of the entire molecule. For this reason, the nucleic acid sequence is also termed the Biomolecular structure#Primary structure, primary structure. The sequence represents genetic information. Biological deoxyribonucleic acid represents the information which directs the functions of an organism. Nucleic acids also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Purine
Purine is a heterocyclic aromatic organic compound that consists of two rings (pyrimidine and imidazole) fused together. It is water-soluble. Purine also gives its name to the wider class of molecules, purines, which include substituted purines and their tautomers. They are the most widely occurring nitrogen-containing heterocycles in nature. Dietary sources Purines are found in high concentration in meat and meat products, especially internal organs, such as liver and kidney, and in various seafoods, high-fructose beverages, alcohol, and yeast products. Examples of high-purine food sources include anchovies, sardines, liver, beef, kidneys, brains, monkfish, dried mackerel, and shrimp. Foods particularly rich in hypoxanthine, adenine, and guanine lead to higher blood levels of uric acid. Foods having more than 200 mg of hypoxanthine per 100 g, particularly animal and fish meats containing hypoxanthine as more than 50% of total purines, are more likely to increase uri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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DDX3X
ATP-dependent RNA helicase DDX3X is an enzyme that in humans is encoded by the ''DDX3X'' gene. Function DEAD box proteins are putative RNA helicases characterized by the conserved motif Asp-Glu-Ala-Asp (DEAD). They are implicated in a number of cellular processes involving alteration of RNA secondary structure, such as translation initiation, nuclear and mitochondrial splicing, and ribosome and spliceosome assembly. Based on their distribution patterns, some members of this family are believed to be involved in embryogenesis, spermatogenesis, and cellular growth and division. This gene encodes a DEAD box protein, which interacts specifically with the hepatitis C virus core protein, resulting in a change in intracellular location. This gene has a homolog located in the nonrecombining region of the Y chromosome. The protein sequence is 91% identical between this gene and the Y-linked homolog. DDX3X attenuates RNA-RNA interactions within G3BP1-driven RNP granules. Destabi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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DHX29
DExH-box helicase 29 (DHX29) is a 155 kDa protein that in humans is encoded by the DHX29 gene. Function This gene encodes a member of the DEAH (Asp-Glu-Ala-His) subfamily of proteins, part of the DEAD (Asp-Glu-Ala-Asp) box family of RNA helicases. The encoded protein functions in translation initiation, and is specifically required for ribosomal scanning across stable mRNA secondary structures during initiation codon selection. This protein may also play a role in sensing virally derived cytosolic nucleic acids. Knockdown of this gene results in reduced protein translation and impaired proliferation of cancer cells. Interactions DHX29 has been shown to interact with the eukaryotic small ribosomal subunit (40S) and eIF3. See also *Eukaryotic translation Eukaryotic translation is the biological process by which messenger RNA is Translation (biology), translated into proteins in eukaryotes. It consists of four phases: initiation, elongation, termination, and recapping. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Eukaryotic Initiation
The eukaryotes ( ) constitute the domain of Eukaryota or Eukarya, organisms whose cells have a membrane-bound nucleus. All animals, plants, fungi, seaweeds, and many unicellular organisms are eukaryotes. They constitute a major group of life forms alongside the two groups of prokaryotes: the Bacteria and the Archaea. Eukaryotes represent a small minority of the number of organisms, but given their generally much larger size, their collective global biomass is much larger than that of prokaryotes. The eukaryotes emerged within the archaeal kingdom Promethearchaeati and its sole phylum Promethearchaeota. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among the Archaea. Eukaryotes first emerged during the Paleoproterozoic, likely as flagellated cells. The leading evolutionary theory is they were created by symbiogenesis between an anaerobic Promethearchaeati archaean and an aerobic proteobacterium, which formed the mitoc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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7-Methylguanosine
7-Methylguanosine (m7G) is a modified purine nucleoside. It is a methylated version of guanosine and when found in human urine, it may be a biomarker of some types of cancer. In the RNAs, 7-methylguanosine have been used to study and examine the reaction evolving methylguanosine. It also participates in the formation of 5'-cap that stabilizes mRNA In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of Protein biosynthesis, synthesizing a protein. mRNA is ... and prevents its degradation by 5' exonucleases. See also * m7G(5')pppN diphosphatase * METTL1 * Messenger RNA decapping * 23S rRNA (guanine2445-N2)-methyltransferase * 16S rRNA (guanine527-N7)-methyltransferase * N1-Methylguanosine (m1G) References External links Metabocard for 7-Methylguanosine (HMDB01107) Human Metabolome Database, University of Alberta Nucleosides Purines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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PABPC1
Polyadenylate-binding protein 1 is a protein that in humans is encoded by the ''PABPC1'' gene. The protein PABP1 binds mRNA and facilitates a variety of functions such as transport into and out of the nucleus, degradation, translation, and stability. There are two separate PABP1 proteins, one which is located in the nucleus (PABPN1) and the other which is found in the cytoplasm (PABPC1). The location of PABP1 affects the role of that protein and its function with RNA. Function The poly(A)-binding protein (PAB or PABP), which is found complexed to the 3' poly(A) tail of eukaryotic mRNA, is required for poly(A) lengthening and the termination of translation. In humans, the PABPs comprise a small nuclear isoform and a conserved gene family of other poly(A)-binding proteins. upplied by OMIMref name="entrez"> PABPC1 is usually diffused within the cytoplasm and concentrated at sites of high mRNA concentration such as stress granules, processing bodies, and locations of high transla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Eukaryotic Initiation Factor 3
Eukaryotic initiation factor 3 (eIF3) is a multiprotein complex that functions during the initiation phase of eukaryotic translation. It is essential for most forms of cap-dependent and cap-independent translation initiation. In humans, eIF3 consists of 13 nonidentical subunits (eIF3a-m) with a combined molecular weight of ~800 kDa, making it the largest translation initiation factor. The eIF3 complex is broadly conserved across eukaryotes, but the conservation of individual subunits varies across organisms. For instance, while most mammalian eIF3 complexes are composed of 13 subunits, budding yeast's eIF3 has only six subunits (eIF3a, b, c, g, i, j). Function eIF3 stimulates nearly all steps of translation initiation. eIF3 also appears to participate in other phases of translation, such as recycling, where it promotes the splitting of post-termination ribosomes. In specialized cases of reinitiation following uORFs, eIF3 may remain bound to the ribosome through elongation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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EIF5
Eukaryotic translation initiation factor 5 is a protein that in humans is encoded by the ''EIF5'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei .... EIF5 is a GTPase-activating protein. References External links Cap-dependent translation initiationfrom Nature Reviews Microbiology. A good image and overview of the function of initiation factors PDBe-KBprovides an overview of all the structure information available in the PDB for Human Eukaryotic translation initiation factor 5 (EIF5) Further reading * * * * * * * * * * * * * * * * * {{gene-14-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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EIF1
Eukaryotic translation initiation factor 1 (eIF1) is a protein that in humans is encoded by the ''EIF1'' gene. It is related to yeast SUI1. eIF1 interacts with the eukaryotic small ( 40S) ribosomal subunit and eIF3, and is a component of the 43S preinitiation complex (PIC). eIF1 and eIF1A bind cooperatively to the 40S to stabilize an "open" conformation of the preinitiation complex (PIC) during eukaryotic translation Eukaryotic translation is the biological process by which messenger RNA is Translation (biology), translated into proteins in eukaryotes. It consists of four phases: initiation, elongation, termination, and recapping. Initiation Translation init ... initiation. eIF1 binds to a region near the ribosomal P-site in the 40S subunit and functions in a manner similar to the structurally related bacterial counterpart IF3. Structure eIF1 is a conserved translation protein in all eukaryotic cells that is responsible for the investigation of codon-anticodon mismatches ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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EIF2
Eukaryotic Initiation Factor 2 (eIF2) is a eukaryotic initiation factor. It is required for most forms of eukaryotic translation initiation. eIF2 mediates the binding of tRNAiMet to the ribosome in a GTP-dependent manner. eIF2 is a heterotrimer consisting of an alpha (also called subunit 1, EIF2S1), a beta (subunit 2, EIF2S2), and a gamma (subunit 3, EIF2S3) subunit. Once the initiation phase has completed, eIF2 is released from the ribosome bound to GDP as an inactive binary complex. To participate in another round of translation initiation, this GDP must be exchanged for GTP. Function eIF2 is an essential factor for protein synthesis that forms a ternary complex (TC) with GTP and the initiator Met- tRNAiMet. After its formation, the TC binds the 40S ribosomal subunit to form the 43S preinitiation complex (43S PIC). 43S PIC assembly is believed to be stimulated by the initiation factors eIF1, eIF1A, and the eIF3 complex according to ''in vitro'' experiments. The 43 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Ribosome
Ribosomes () are molecular machine, macromolecular machines, found within all cell (biology), cells, that perform Translation (biology), biological protein synthesis (messenger RNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA molecules to form polypeptide chains. Ribosomes consist of two major components: the small and large ribosomal subunits. Each subunit consists of one or more ribosomal RNA molecules and many ribosomal proteins (). The ribosomes and associated molecules are also known as the ''translational apparatus''. Overview The sequence of DNA that encodes the sequence of the amino acids in a protein is transcribed into a messenger RNA (mRNA) chain. Ribosomes bind to the messenger RNA molecules and use the RNA's sequence of nucleotides to determine the sequence of amino acids needed to generate a protein. Amino acids are selected and carried to the ribosome by transfer RNA (tRNA) molecules, which enter the riboso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |