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SMG6
Telomerase-binding protein EST1A is an enzyme that in humans is encoded by the ''SMG6'' gene on Chromosome 17 (human), chromosome 17. It is ubiquitously expressed in many tissues and cell types. The C-terminus of the EST1A protein contains a PIN domain, PilT N-terminus (PIN) domain. This structure for this domain has been determined by X-ray crystallography. SMG6 functions to bind single-stranded DNA in telomere maintenance and Single-stranded DNA, single-stranded RNA in nonsense-mediated mRNA decay (NMD). The ''SMG6'' gene also contains one of 27 SNPs associated with increased risk of coronary artery disease. Structure Gene The ''SMG6'' gene resides on chromosome 17 at the band 17p13.3 and contains 30 Exon, exons. This gene produces 3 isoforms through alternative splicing. Protein SMG6 is one of three human homologs for Est1p found in Saccharomyces cerevisiae. It contains a PIN domain, which is characteristic of proteins with ribonuclease activity. The PIN domain forms an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SMG5
Protein SMG5 is a protein that in humans is encoded by the ''SMG5'' gene. This protein contains a PIN domain that appears to have mutated the residues in the active site. References Further reading * * * * * * * * * * * {{gene-1-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PIN Domain
In molecular biology the PIN domain is a protein domain that is about 130 amino acids in length. PIN domains function as nuclease enzymes that cleave single stranded RNA in a sequence- or structure-dependent manner. PIN domains contain four nearly invariant acidic residues. Crystal structures show these residues clustered together in the putative active site. In eukaryotes PIN domains are found in proteins involved in nonsense mediated mRNA decay, in proteins such as SMG5 and SMG6, and in processing of 18S ribosomal RNA Ribosomal ribonucleic acid (rRNA) is a type of non-coding RNA which is the primary component of ribosomes, essential to all cells. rRNA is a ribozyme which carries out protein synthesis in ribosomes. Ribosomal RNA is transcribed from ribosomal .... The majority of PIN-domain proteins found in prokaryotes are the toxic components of toxin-antitoxin operons. These loci provide a control mechanism that helps free-living prokaryotes cope with nutritional stress ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclease
A nuclease (also archaically known as nucleodepolymerase or polynucleotidase) is an enzyme capable of cleaving the phosphodiester bonds between nucleotides of nucleic acids. Nucleases variously effect single and double stranded breaks in their target molecules. In living organisms, they are essential machinery for many aspects of DNA repair. Defects in certain nucleases can cause genetic instability or immunodeficiency. Nucleases are also extensively used in molecular cloning. There are two primary classifications based on the locus of activity. Exonucleases digest nucleic acids from the ends. Endonucleases act on regions in the ''middle'' of target molecules. They are further subcategorized as deoxyribonucleases and ribonucleases. The former acts on DNA, the latter on RNA. History In the late 1960s, scientists Stuart Linn and Werner Arber isolated examples of the two types of enzymes responsible for phage growth restriction in Escherichia coli ( E. coli) bacteria. One of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genome-wide Association Study
In genomics, a genome-wide association study (GWA study, or GWAS), also known as whole genome association study (WGA study, or WGAS), is an observational study of a genome-wide set of Single-nucleotide polymorphism, genetic variants in different individuals to see if any variant is associated with a trait. GWA studies typically focus on associations between single-nucleotide polymorphisms (SNPs) and traits like major human diseases, but can equally be applied to any other genetic variants and any other organisms. When applied to human data, GWA studies compare the DNA of participants having varying phenotypes for a particular trait or disease. These participants may be people with a disease (cases) and similar people without the disease (controls), or they may be people with different phenotypes for a particular trait, for example blood pressure. This approach is known as phenotype-first, in which the participants are classified first by their clinical manifestation(s), as oppose ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SMG1
Serine/threonine-protein kinase SMG1 is an enzyme that in humans is encoded by the ''SMG1'' gene. SMG1 belongs to the phosphatidylinositol 3-kinase-related kinase protein family. Function This gene encodes a protein involved in nonsense-mediated mRNA decay (NMD) as part of the mRNA surveillance complex. The protein has kinase activity and is thought to function in NMD by phosphorylating the regulator of nonsense transcripts 1 protein. Alternative spliced transcript variants have been described, but their full-length natures have not been determined. Interactions SMG1 (gene) has been shown to interact with PRKCI Protein kinase C iota type is an enzyme that in humans is encoded by the ''PRKCI'' gene. Function This gene encodes a member of the protein kinase C (PKC) family of serine/threonine protein kinases. The PKC family comprises at least eight membe ... and UPF1. References Further reading * * * * * * * * * * * * * * EC 2.7.11 Genes o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premature Translation Termination Codons , a horror short story by American writer Edgar Allan Poe, published in 1844.
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Premature may refer to: * ''Premature'' (2014 film), an American comedy film * ''Premature'' (2019 film), an American romantic drama film * ''PREMature'', a 2015 British television drama miniseries See also * Premature aging, of an organism * Premature birth, a preterm baby birth * Premature ejaculation, a condition in which a man ejaculates earlier than he or his partner would like him to * Adult premature aging syndrome, a disease with the appearance of premature aging * Premature Burial Premature burial, also known as live burial, burial alive, or vivisepulture, means to be buried while still alive. Animals or humans may be buried alive accidentally on the mistaken assumption that they are dead, or intentionally as a form of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonsense Mediated Decay
Nonsense-mediated mRNA decay (NMD) is a surveillance pathway that exists in all eukaryotes. Its main function is to reduce errors in gene expression by eliminating mRNA transcripts that contain premature stop codons. Translation of these aberrant mRNAs could, in some cases, lead to deleterious gain-of-function or dominant-negative activity of the resulting proteins. NMD was first described in human cells and in yeast almost simultaneously in 1979. This suggested broad phylogenetic conservation and an important biological role of this intriguing mechanism. NMD was discovered when it was realized that cells often contain unexpectedly low concentrations of mRNAs that are transcribed from alleles carrying nonsense mutations. Nonsense mutations code for a premature stop codon which causes the protein to be shortened. The truncated protein may or may not be functional, depending on the severity of what is not translated. In human genetics, NMD has the possibility to not only limit the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endonuclease
Endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain. Some, such as deoxyribonuclease I, cut DNA relatively nonspecifically (without regard to sequence), while many, typically called restriction endonucleases or restriction enzymes, cleave only at very specific nucleotide sequences. Endonucleases differ from exonucleases, which cleave the ends of recognition sequences instead of the middle (endo) portion. Some enzymes known as "exo-endonucleases", however, are not limited to either nuclease function, displaying qualities that are both endo- and exo-like. Evidence suggests that endonuclease activity experiences a lag compared to exonuclease activity. Restriction enzymes are endonucleases from eubacteria and archaea that recognize a specific DNA sequence. The nucleotide sequence recognized for cleavage by a restriction enzyme is called the restriction site. Typically, a restriction site will be a palindromic sequence about four to six nucleotides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telomerase
Telomerase, also called terminal transferase, is a ribonucleoprotein that adds a species-dependent telomere repeat sequence to the 3' end of telomeres. A telomere is a region of repetitive sequences at each end of the chromosomes of most eukaryotes. Telomeres protect the end of the chromosome from DNA damage or from fusion with neighbouring chromosomes. The fruit fly ''Drosophila melanogaster'' lacks telomerase, but instead uses retrotransposons to maintain telomeres. Telomerase is a reverse transcriptase enzyme that carries its own RNA molecule (e.g., with the sequence 3′- CCC AA UCCC-5′ in ''Trypanosoma brucei'') which is used as a template when it elongates telomeres. Telomerase is active in gametes and most cancer cells, but is normally absent from, or at very low levels in, most somatic cells. History The existence of a compensatory mechanism for telomere shortening was first found by Soviet biologist Alexey Olovnikov in 1973, who also suggested the telomere hypothe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UPF1
Regulator of nonsense transcripts 1 is a protein that in humans is encoded by the ''UPF1'' gene. Function This gene encodes a protein that is part of a post-splicing multiprotein complex, the exon junction complex, involved in both mRNA nuclear export and mRNA surveillance. mRNA surveillance detects exported mRNAs with truncated open reading frames and initiates nonsense-mediated mRNA decay (NMD). When translation ends upstream from the last exon-exon junction, this triggers NMD to degrade mRNAs containing premature stop codons. This protein is located in both the cytoplasm and nucleus of the cell. When translation ends, it interacts with the protein that is a functional homolog of yeast Upf2p to trigger mRNA decapping. Use of multiple polyadenylation sites has been noted for this gene. Interactions UPF1 has been shown to interact with: * DCP1A, * DCP2, * SMG1, * UPF2, * UPF3A, and * UPF3B Regulator of nonsense transcripts 3B is a protein that in humans is encoded by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Complexes
A protein complex or multiprotein complex is a group of two or more associated polypeptide chains. Protein complexes are distinct from multienzyme complexes, in which multiple catalytic domains are found in a single polypeptide chain. Protein complexes are a form of quaternary structure. Proteins in a protein complex are linked by non-covalent protein–protein interactions. These complexes are a cornerstone of many (if not most) biological processes. The cell is seen to be composed of modular supramolecular complexes, each of which performs an independent, discrete biological function. Through proximity, the speed and selectivity of binding interactions between enzymatic complex and substrates can be vastly improved, leading to higher cellular efficiency. Many of the techniques used to enter cells and isolate proteins are inherently disruptive to such large complexes, complicating the task of determining the components of a complex. Examples of protein complexes include the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
