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AlkB
AlkB (Alkylation B) is a protein found in E. coli, induced during an adaptive response and involved in the direct reversal of alkylation damage.Errol C.Friedberg, Graham c. Walker, Wolfram Siede, Richard D. Wood, Roger A. schultz, Tom Ellenberger, ''DNA Repair and Mutagenesis'', 2nd Edition, ASM press, AlkB specifically removes alkylation damage to single stranded (SS) DNA caused by SN2 type of chemical agents. It efficiently removes methyl groups from 1-methyl adenines, 3-methyl cytosines in SS DNA. AlkB is an alpha-ketoglutarate-dependent hydroxylase, a superfamily non-haem iron-containing proteins. It oxidatively demethylates the DNA substrate. Demethylation by AlkB is accompanied with release of CO2, succinate, and formaldehyde. Human homologs There are nine human homologs of AlkB. They are: * ''Alkb homolog 1, histone h2a dioxygenase'', , , , AlkB homolog 5, RNA demethylase, , , , ABH3, like E. coli AlkB, is specific for SS DNA and RNA whereas ABH2 has higher affinit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptive Response
The adaptive response is a form of direct DNA repair in '' E. coli'' that protects DNA from damage by external agents or by errors during replication.Landini, P, Volkert MR. (2000Regulatory Responses of the Adaptive Response to Alkylation Damage: a Simple Regulon with Complex Regulatory Features''J. Bacteriol.'' 182(23): 6543–6549. It is initiated against alkylation, particularly methylation, of guanine or thymine nucleotides or phosphate groups on the sugar-phosphate backbone of DNA. Under sustained exposure to low-level treatment with alkylating mutagens, ''E. coli'' can adapt to the presence of the mutagen, rendering subsequent treatment with high doses of the same agent less effective.Volkert MR. (1988)Adaptive response of ''Escherichia coli'' to alkylation damage.''Environ Mol Mutagen'' 11(2):241-55. This mechanism has four related genes, also known as “SOS genes”: ada, alkA, alkB, and aidB, each one working in specific residues, all regulated by ada protein. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkb Homolog 1, Histone H2a Dioxygenase
AlkB homolog 1, histone H2A dioxygenase is a protein that in humans is encoded by the ALKBH1 gene. Function This gene encodes a homolog to the '' E. coli'' alkB gene product. The E. coli alkB protein is part of the adaptive response mechanism of DNA alkylation damage repair. It is involved in damage reversal by oxidative demethylation Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ... of 1-methyladenine and 3-methylcytosine. [provided by RefSeq, Jul 2008]. References Further reading * * * * * * * * * {{NLM content ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N6-Methyladenosine
''N''6-Methyladenosine (m6A) was originally identified and partially characterised in the 1970s, and is an abundant modification in mRNA and DNA. It is found within some viruses, and most eukaryotes including mammals, insects, plants and yeast. It is also found in tRNA, rRNA, and small nuclear RNA (snRNA) as well as several long non-coding RNA, such as '' Xist''. The methylation of adenosine is directed by a large m6A methyltransferase complex containing METTL3 as the SAM-binding sub-unit. ''In vitro'', this methyltransferase complex preferentially methylates RNA oligonucleotides containing GGACU and a similar preference was identified ''in vivo'' in mapped m6A sites in Rous sarcoma virus genomic RNA and in bovine prolactin mRNA. More recent studies have characterized other key components of the m6A methyltransferase complex in mammals, including METTL14, Wilms tumor 1 associated protein (WTAP), KIAA1429 and METTL5. Following a 2010 speculation of m6A in mRNA being dynamic and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid resid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proteins
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residues in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potyvirus
''Potyvirus'' is a genus of positive-strand RNA viruses in the family ''Potyviridae''. Plants serve as natural hosts. The genus is named after member virus ''potato virus Y''. Potyviruses account for about thirty percent of the currently known plant viruses. Like begomoviruses, members of this genus may cause significant losses in agricultural, pastoral, horticultural, and ornamental crops. More than 200 species of aphids spread potyviruses, and most are from the subfamily ''Aphidinae'' (genera ''Macrosiphum'' and ''Myzus''). The genus contains 190 species. Virology Structure The virion is non-enveloped with a flexuous and filamentous nucleocapsid, 680 to 900 nanometers (nm) long and is 11–20 nm in diameter. The nucleocapsid contains around 2000 copies of the capsid protein. The symmetry of the nucleocapsid is helical with a pitch of 3.4 nm. Genome The genome is a linear, positive-sense, single-stranded RNA ranging in size from 9,000–12,000 nucleotide bas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potyviridae
''Potyviridae'' is a family of positive-strand RNA viruses that encompasses more than 30% of known plant viruses, many of which are of great agricultural significance. The family has 12 genera and 235 species, three of which are unassigned to a genus. Structure Potyvirid virions are nonenveloped, flexuous filamentous, rod-shaped particles. The diameter is around 12–15 nm, with a length of 200–300 nm. Genome Genomes are linear and usually nonsegmented, around 8–12kb in length, consisting of positive-sense RNA, which is surrounded by a protein coat made up of a single viral encoded protein called a capsid. All induce the formation of virus inclusion bodies called cylindrical inclusions (‘pinwheels’) in their hosts. These consist of a single protein (about 70 kDa) made in their hosts from a single viral genome product. Member viruses encode large polypeptides that are cleaved into mature proteins. In 5'–3' order these proteins are * P1 (a serine prot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 synthesizing a protein. mRNA is created during the process of transcription, where an enzyme ( RNA polymerase) converts the gene into primary transcript mRNA (also known as pre-mRNA). This pre-mRNA usually still contains introns, regions that will not go on to code for the final amino acid sequence. These are removed in the process of RNA splicing, leaving only exons, regions that will encode the protein. This exon sequence constitutes mature mRNA. Mature mRNA is then read by the ribosome, and, utilising amino acids carried by transfer RNA (tRNA), the ribosome creates the protein. This process is known as translation. All of these processes form part of the central dogma of molecular biology, which describes the flow of genetic information in a biological system. As in DNA, gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Demethylase
Demethylases are enzymes that remove methyl (CH3) groups from nucleic acids, proteins (particularly histones), and other molecules. Demethylases are important epigenetic proteins, as they are responsible for transcriptional regulation of the genome by controlling the methylation of DNA and histones, and by extension, the chromatin state at specific gene loci. Histone lysine demethylation Histone methylation was initially considered an effectively irreversible process as the half-life of the histone methylation was approximately equal to the histone half-life. Histone lysine demethylase LSD1 (later classified as KDM1A) was first identified in 2004 as a nuclear amine oxidase homolog. Two main classes of histone lysine demethylases exist, defined by their mechanisms: flavin adenine dinucleotide (FAD)-dependent amine oxidases and α-ketoglutarate-dependent hydroxylases. Histone lysine demethylases possess a variety of domains that are responsible for histone recognition, DN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FTO Gene
Fat mass and obesity-associated protein also known as alpha-ketoglutarate-dependent dioxygenase FTO is an enzyme that in humans is encoded by the ''FTO'' gene located on Chromosome 16 (human), chromosome 16. As one homolog in the AlkB family proteins, it is the first mRNA demethylase that has been identified. Certain alleles of the FTO gene appear to be correlated with obesity in humans. Function The amino acid sequence (biology), sequence of the transcription (genetics), transcribed FTO protein shows high similarity with the enzyme AlkB which oxidatively demethylation, demethylates DNA. FTO is a member of the superfamily of alpha-ketoglutarate-dependent hydroxylase, which are non-heme iron-containing proteins. Recombinant FTO protein was first discovered to catalyze demethylation of 3-methylthymine in single-stranded DNA, and 3-methyluridine in single-stranded RNA, with low efficiency. The nucleoside N6-methyladenosine (m6A), an abundant modification in RNA, was then found to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Obesity
Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's weight divided by the square of the person's height—is over ; the range is defined as overweight. Some East Asian countries use lower values to calculate obesity. Obesity is a major cause of disability and is correlated with various diseases and conditions, particularly cardiovascular diseases, type 2 diabetes, obstructive sleep apnea, certain types of cancer, and osteoarthritis. Obesity has individual, socioeconomic, and environmental causes. Some known causes are diet, physical activity, automation, urbanization, genetic susceptibility, medications, mental disorders, economic policies, endocrine disorders, and exposure to endocrine-disrupting chemicals. While a majority of obese individuals at any given time are attempti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ALKBH8
TRNA (carboxymethyluridine34-5-O)-methyltransferase (, ''ALKBH8'', ''ABH8'', ''Trm9'', ''tRNA methyltransferase 9'') is an enzyme with systematic name ''S-adenosyl-L-methionine:tRNA (carboxymethyluridine34-5-O)-methyltransferase''. This enzyme catalyses the following chemical reaction : S-adenosyl-L-methionine + carboxymethyluridine34 in tRNA \rightleftharpoons S-adenosyl-L-homocysteine + 5-(2-methoxy-2-oxoethyl)uridine34 in tRNA The enzyme catalyses the posttranslational modification of uridine residues at the wobble position 34 of the anticodon 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 a ... loop of tRNA. References External links * {{Portal bar, Biology, border=no EC 2.1.1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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