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Formylmethionine
''N''-Formylmethionine (fMet, HCO-Met, For-Met) is a derivative of the amino acid methionine in which a formyl group has been added to the amino group. It is specifically used for initiation of protein synthesis from bacterial and organellar genes, and may be removed post-translationally. fMet plays a crucial part in the protein synthesis of bacteria, mitochondria and chloroplasts. It is not used in cytosolic protein synthesis of eukaryotes, where eukaryotic nuclear genes are translated. It is also not used by Archaea. In the human body, fMet is recognized by the immune system as foreign material, or as an alarm signal released by damaged cells, and stimulates the body to fight against potential infection. Function in protein synthesis fMet is a starting residue in the synthesis of proteins in bacteria, and, consequently, is located at the ''N''-terminus of the growing polypeptide. fMet is delivered to the ribosome (30S) - mRNA complex by a specialized tRNA (tRNAfM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amino Acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha amino acids appear in the genetic code. Amino acids can be classified according to the locations of the core structural functional groups, as Alpha and beta carbon, alpha- , beta- , gamma- or delta- amino acids; other categories relate to Chemical polarity, polarity, ionization, and side chain group type (aliphatic, Open-chain compound, acyclic, aromatic, containing hydroxyl or sulfur, etc.). In the form of proteins, amino acid '' residues'' form the second-largest component (water being the largest) of human muscles and other tissues. Beyond their role as residues in proteins, amino acids participate in a number of processes such as neurotransmitter transport and biosynthesis. It is thought that they played a key role in enabling life ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Codon
The genetic code is the set of rules used by living cells to translate information encoded within genetic material ( DNA or RNA sequences of nucleotide triplets, or codons) into proteins. Translation is accomplished by the ribosome, which links proteinogenic amino acids in an order specified by messenger RNA (mRNA), using transfer RNA (tRNA) molecules to carry amino acids and to read the mRNA three nucleotides at a time. The genetic code is highly similar among all organisms and can be expressed in a simple table with 64 entries. The codons specify which amino acid will be added next during protein biosynthesis. With some exceptions, a three-nucleotide codon in a nucleic acid sequence specifies a single amino acid. The vast majority of genes are encoded with a single scheme (see the RNA codon table). That scheme is often referred to as the canonical or standard genetic code, or simply ''the'' genetic code, though variant codes (such as in mitochondria) exist. History Efforts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methionine
Methionine (symbol Met or M) () is an essential amino acid in humans. As the precursor of other amino acids such as cysteine and taurine, versatile compounds such as SAM-e, and the important antioxidant glutathione, methionine plays a critical role in the metabolism and health of many species, including humans. It is encoded by the codon AUG. Methionine is also an important part of angiogenesis, the growth of new blood vessels. Supplementation may benefit those suffering from copper poisoning. Overconsumption of methionine, the methyl group donor in DNA methylation, is related to cancer growth in a number of studies. Methionine was first isolated in 1921 by John Howard Mueller. Biochemical details Methionine (abbreviated as Met or M; encoded by the codon AUG) is an α-amino acid that is used in the biosynthesis of proteins. It contains a carboxyl group (which is in the deprotonated −COO− form under biological pH conditions), an amino group (which is in the protonated fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methionine Aminopeptidase
Methionyl aminopeptidase (, ''methionine aminopeptidase'', ''peptidase M'', ''L-methionine aminopeptidase'', ''MAP'') is an enzyme. This enzyme catalyses the following chemical reaction : Release of N-terminal amino acids, preferentially methionine, from peptides and arylamides This membrane-bound enzymatic activity is present in both prokaryotes and eukaryotes. Proteins possessing this activity include METAP1 and METAP2 Methionine aminopeptidase 2 is an enzyme that in humans is encoded by the ''METAP2'' gene. Methionine aminopeptidase 2, a member of the dimetallohydrolase family, is a cytosolic metalloenzyme that catalyzes the hydrolytic removal of N-terminal m .... References External links * {{Portal bar, Biology, border=no EC 3.4.11 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-terminus
The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the amine group is bonded to the carboxylic group of another amino acid, making it a chain. That leaves a free carboxylic group at one end of the peptide, called the C-terminus, and a free amine group on the other end called the N-terminus. By convention, peptide sequences are written N-terminus to C-terminus, left to right (in LTR writing systems). This correlates the translation direction to the text direction, because when a protein is translated from messenger RNA, it is created from the N-terminus to the C-terminus, as amino acids are added to the carboxyl end of the protein. Chemistry Each amino acid has an amine group and a carboxylic group. Amino acids link to one another by peptide bonds which form through a dehydration reaction that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic relationsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRNA
Transfer RNA (abbreviated tRNA and formerly referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes), that serves as the physical link between the mRNA and the amino acid sequence of proteins. tRNAs genes from Bacteria are typically shorter (mean = 77.6 bp) than tRNAs from Archaea (mean = 83.1 bp) and eukaryotes (mean = 84.7 bp). The mature tRNA follows an opposite pattern with tRNAs from Bacteria being usually longer (median = 77.6 nt) than tRNAs from Archaea (median = 76.8 nt), with eukaryotes exhibiting the shortest mature tRNAs (median = 74.5 nt). Transfer RNA (tRNA) does this by carrying an amino acid to the protein synthesizing machinery of a cell called the ribosome. Complementation of a 3-nucleotide codon in a messenger RNA (mRNA) by a 3-nucleotide anticodon of the tRNA results in protein synthesis based on the mRNA code. As such, tRNAs are a necessary component of translation, the biological ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondria
A mitochondrion (; ) is an organelle found in the Cell (biology), cells of most Eukaryotes, such as animals, plants and Fungus, fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'' was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase coined by Philip Siekevitz in a 1957 article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). A large number of unicellular organisms, such as microsporidia, parabasalids and diplomonads, have reduced or transformed their mitochondria into mitosome, other structures. One eukaryote, ''Monocercomonoides'', is known to have completely lost its mitocho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BioEssays
''BioEssays'' is a monthly peer-reviewed review journal covering molecular and cellular biology. Areas covered include genetics, genomics, epigenetics, evolution, developmental biology, neuroscience, human biology, physiology, systems biology, and plant biology. The journal also publishes commentaries on aspects of science communication, education, policy, and current affairs. History The journal was established in December 1984 by founding editor-in-chief William J. Whelan under the auspices of the International Union of Biochemistry and Molecular Biology. Adam S. Wilkins became editor in January 1990. Originally published by ICSU Press and The Company of Biologists, ''BioEssays'' has been published by John Wiley & Sons since January 1998. Andrew Moore became editor-in-chief in August 2008. Kerstin Brachhold is current editor-in-chief. Post-publication commenting ''BioEssays'' offers an article-commenting facility via its website. Topics of particular current attention are of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peptide Deformylase
In enzymology, a peptide deformylase () is an enzyme that catalyzes the chemical reaction :H2O + formyl-L-methionyl peptide \rightleftharpoons methionyl peptide + formate Thus, the two substrates of this enzyme are formyl-L-methionyl peptide and H2O, whereas its two products are formate and methionyl peptide. This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in linear amides. The systematic name of this enzyme class is formyl-L-methionyl peptide amidohydrolase. Structural studies As of late 2007, 34 structures have been solved for this class of enzymes, with PDB accession codes , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , and . See also *Actinonin Actinonin is a naturally occurring antibacterial agent that has demonstrated anti-tumor activity. Actiononin has been shown to inhibit the enzyme peptide deformylase, which is essential in prokaryote A prokaryote () is a sing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aminoacyl-tRNA Synthetase
An aminoacyl-tRNA synthetase (aaRS or ARS), also called tRNA-ligase, is an enzyme that attaches the appropriate amino acid onto its corresponding tRNA. It does so by catalyzing the transesterification of a specific cognate amino acid or its precursor to one of all its compatible cognate tRNAs to form an aminoacyl-tRNA. In humans, the 20 different types of aa-tRNA are made by the 20 different aminoacyl-tRNA synthetases, one for each amino acid of the genetic code. This is sometimes called "charging" or "loading" the tRNA with an amino acid. Once the tRNA is charged, a ribosome can transfer the amino acid from the tRNA onto a growing peptide, according to the genetic code. Aminoacyl tRNA therefore plays an important role in RNA translation, the expression of genes to create proteins. Mechanism The synthetase first binds ATP and the corresponding amino acid (or its precursor) to form an aminoacyl-adenylate, releasing inorganic pyrophosphate (PPi). The adenylate-aaRS complex th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
