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Shine–Dalgarno Sequence
The Shine–Dalgarno (SD) sequence is a ribosomal binding site in bacterial and archaeal messenger RNA, generally located around 8 bases upstream of the start codon AUG. The RNA sequence helps recruit the ribosome to the messenger RNA (mRNA) to initiate protein synthesis by aligning the ribosome with the start codon. Once recruited, tRNA may add amino acids in sequence as dictated by the codons, moving downstream from the translational start site. The Shine–Dalgarno sequence is common in bacteria, but rarer in archaea. It is also present in some chloroplast and mitochondrial transcripts. The six-base consensus sequence is AGGAGG; in ''Escherichia coli'', for example, the sequence is AGGAGGU, while the shorter dominates in ''E. coli'' virus T4 early genes. The Shine–Dalgarno sequence was proposed by Australian scientists John Shine and Lynn Dalgarno. Recognition Translation start sites Using a method developed by Hunt, Shine and Dalgarno showed that the nucleotide tract a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribosomal Binding Site
A ribosome binding site, or ribosomal binding site (RBS), is a sequence of nucleotides upstream of the start codon of an mRNA transcript that is responsible for the recruitment of a ribosome during the initiation of translation. Mostly, RBS refers to bacterial sequences, although internal ribosome entry sites (IRES) have been described in mRNAs of eukaryotic cells or viruses that infect eukaryotes. Ribosome recruitment in eukaryotes is generally mediated by the 5' cap present on eukaryotic mRNAs. Prokaryotes The RBS in prokaryotes is a region upstream of the start codon. This region of the mRNA has the consensus 5'-AGGAGG-3', also called the Shine-Dalgarno (SD) sequence. The complementary sequence (CCUCCU), called the anti-Shine-Dalgarno (ASD) is contained in the 3’ end of the 16S region of the smaller (30S) ribosomal subunit. Upon encountering the Shine-Dalgarno sequence, the ASD of the ribosome base pairs with it, after which translation is initiated. Variations of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Shine
John Shine (born 3 July 1946) is an Australian biochemist and molecular biologist. Shine and Lynn Dalgarno discovered the nucleotide sequence, called the Shine-Dalgarno sequence, necessary for the initiation and termination of protein synthesis. He directed the Garvan Institute of Medical Research in Sydney from 1990 to 2011. In May 2018 Shine was elected President of the Australian Academy of Science. Background and early career The brother of scientist, Richard Shine, John Shine was born in Brisbane in 1946 and completed his university studies at the Australian National University (ANU) in Canberra, graduating with a bachelor of science with honours in 1972 and completing his PhD in 1975. During the course of his studies he and his supervisor, Lynn Dalgarno, discovered the RNA sequence necessary for ribosome binding and the initiation of protein synthesis in the bacterium ''Escherichia coli''. The sequence was named the Shine-Dalgarno sequence. This was a key discover ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacterial Translation
Bacterial translation is the process by which messenger RNA is translated into proteins in bacteria. Initiation Initiation of translation in bacteria involves the assembly of the components of the translation system, which are: the two ribosomal subunits ( 50S and 30S subunits); the mature mRNA to be translated; the tRNA charged with N-formylmethionine (the first amino acid in the nascent peptide); guanosine triphosphate (GTP) as a source of energy, and the three prokaryotic initiation factors IF1, IF2, and IF3, which help the assembly of the initiation complex. Variations in the mechanism can be anticipated. The ribosome has three active sites: the A site, the P site, and the E site. The ''A site'' is the point of entry for the aminoacyl tRNA (except for the first aminoacyl tRNA, which enters at the P site). The ''P site'' is where the peptidyl tRNA is formed in the ribosome. And the ''E site'' which is the exit site of the now uncharged tRNA after it gives its amino acid to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryote
Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacteria and Archaea (both prokaryotes) make up the other two domains. The eukaryotes are usually now regarded as having emerged in the Archaea or as a sister of the Asgard archaea. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among archaea. Eukaryotes represent a small minority of the number of organisms, but, due to their generally much larger size, their collective global biomass is estimated to be about equal to that of prokaryotes. Eukaryotes emerged approximately 2.3–1.8 billion years ago, during the Proterozoic eon, likely as flagellated phagotrophs. Their name comes from the Greek εὖ (''eu'', "well" or "good") and κάρυον (''karyon'', "nut" or "kernel"). Euka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kozak Consensus Sequence
The Kozak consensus sequence (Kozak consensus or Kozak sequence) is a nucleic acid motif that functions as the protein translation initiation site in most eukaryotic 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 binding site (RBS), that being either the 5′ cap of a me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Translation (biology)
In molecular biology and genetics, translation is the process in which ribosomes in the cytoplasm or endoplasmic reticulum synthesize proteins after the process of transcription (biology), transcription of DNA to RNA in the cell's nucleus (cell), nucleus. The entire process is called gene expression. In translation, mRNA, messenger RNA (mRNA) is decoded in a ribosome, outside the nucleus, to produce a specific amino acid chain, or polypeptide. The polypeptide later protein folding, folds into an Activation energy, active protein and performs its functions in the Cell (biology), cell. The ribosome facilitates decoding by inducing the binding of Base pair, 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: # Initiation: The ribosome assembles around the target mRNA. The first tRNA is attached a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitosis, or meiosis or other types of damage to DNA (such as pyrimidine dimers caused by exposure to ultraviolet radiation), which then may undergo error-prone repair (especially microhomology-mediated end joining), cause an error during other forms of repair, or cause an error during replication (translesion synthesis). Mutations may also result from insertion or deletion of segments of DNA due to mobile genetic elements. Mutations may or may not produce detectable changes in the observable characteristics (phenotype) of an organism. Mutations play a part in both normal and abnormal biological processes including: evolution, cancer, and the development of the immune system, including junctional diversity. Mutation is the ultimate source o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
F1 Phage
Ff phages (for ''F'' specific ''f''ilamentous phages) is a group of almost identical filamentous bacteriophage, filamentous phage (genus ''Inovirus'') including phages F1 phage, f1, fd, M13 phage, M13 and ZJ/2, which infect Gram-negative bacteria, bacteria bearing the Fertility factor (bacteria), F fertility factor. The Virus#Structure, virion (virus particle) is a flexible filament measuring about 6 by 900 nm, comprising a cylindrical protein tube protecting a single-stranded circular DNA molecule at its core. The phage codes for only 11 gene products, and is one of the simplest viruses known. It has been widely used to study fundamental aspects of molecular biology. George Smith and Greg Winter used f1 and fd for their work on phage display for which they were awarded a share of the 2018 Nobel Prize in Chemistry. Early experiments on Ff phages used M13 to identify gene functions, and M13 was also developed as a cloning vehicle, so the name M13 is sometimes used as an informal syn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryotes
Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacteria and Archaea (both prokaryotes) make up the other two domains. The eukaryotes are usually now regarded as having emerged in the Archaea or as a sister of the Asgard archaea. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among archaea. Eukaryotes represent a small minority of the number of organisms, but, due to their generally much larger size, their collective global biomass is estimated to be about equal to that of prokaryotes. Eukaryotes emerged approximately 2.3–1.8 billion years ago, during the Proterozoic eon, likely as flagellated phagotrophs. Their name comes from the Greek εὖ (''eu'', "well" or "good") and κάρυον (''karyon'', "nut" or "kernel"). Eu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleic Acid Notation
The nucleic acid notation currently in use was first formalized by the International Union of Pure and Applied Chemistry (IUPAC) in 1970. This universally accepted notation uses the Roman characters G, C, A, and T, to represent the four nucleotides commonly found in deoxyribonucleic acids (DNA). Given the rapidly expanding role for genetic sequencing, synthesis, and analysis in biology, some researchers have developed alternate notations to further support the analysis and manipulation of genetic data. These notations generally exploit size, shape, and symmetry to accomplish these objectives. IUPAC notation Degenerate base symbols in biochemistry are an IUPAC representation for a position on a DNA sequence that can have multiple possible alternatives. These should not be confused with non-canonical bases because each particular sequence will have in fact one of the regular bases. These are used to encode the consensus sequence of a population of aligned sequences and are used f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrimidine
Pyrimidine (; ) is an aromatic, heterocyclic, organic compound similar to pyridine (). One of the three diazines (six-membered heterocyclics with two nitrogen atoms in the ring), it has nitrogen atoms at positions 1 and 3 in the ring. The other diazines are pyrazine (nitrogen atoms at the 1 and 4 positions) and pyridazine (nitrogen atoms at the 1 and 2 positions). In nucleic acids, three types of nucleobases are pyrimidine derivatives: cytosine (C), thymine (T), and uracil (U). Occurrence and history The pyrimidine ring system has wide occurrence in nature as substituted and ring fused compounds and derivatives, including the nucleotides cytosine, thymine and uracil, thiamine (vitamin B1) and alloxan. It is also found in many synthetic compounds such as barbiturates and the HIV drug, zidovudine. Although pyrimidine derivatives such as alloxan were known in the early 19th century, a laboratory synthesis of a pyrimidine was not carried out until 1879, when Grimaux reported the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Translation
Translation is the communication of the Meaning (linguistic), meaning of a #Source and target languages, source-language text by means of an Dynamic and formal equivalence, equivalent #Source and target languages, target-language text. The English language draws a terminology, terminological distinction (which does not exist in every language) between ''translating'' (a written text) and ''Language interpretation, interpreting'' (oral or Sign language, signed communication between users of different languages); under this distinction, translation can begin only after the appearance of writing within a language community. A translator always risks inadvertently introducing source-language words, grammar, or syntax into the target-language rendering. On the other hand, such "spill-overs" have sometimes imported useful source-language calques and loanwords that have enriched target languages. Translators, including early translators of sacred texts, have helped shape the very l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
