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Ribonucleases
Ribonuclease (commonly abbreviated RNase) is a type of nuclease that catalyzes the degradation of RNA into smaller components. Ribonucleases can be divided into endoribonucleases and exoribonucleases, and comprise several sub-classes within the EC 2.7 (for the phosphorolytic enzymes) and 3.1 (for the hydrolytic enzymes) classes of enzymes. Function All organisms studied contain many RNases of two different classes, showing that RNA degradation is a very ancient and important process. As well as clearing of cellular RNA that is no longer required, RNases play key roles in the maturation of all RNA molecules, both messenger RNAs that carry genetic material for making proteins and non-coding RNAs that function in varied cellular processes. In addition, active RNA degradation systems are the first defense against RNA viruses and provide the underlying machinery for more advanced cellular immune strategies such as RNAi. Some cells also secrete copious quantities of non-specific RN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNase T1
Ribonuclease (commonly abbreviated RNase) is a type of nuclease that catalyzes the degradation of RNA into smaller components. Ribonucleases can be divided into endoribonucleases and exoribonucleases, and comprise several sub-classes within the EC 2.7 (for the phosphorolytic enzymes) and 3.1 (for the hydrolytic enzymes) classes of enzymes. Function All organisms studied contain many RNases of two different classes, showing that RNA degradation is a very ancient and important process. As well as clearing of cellular RNA that is no longer required, RNases play key roles in the maturation of all RNA molecules, both messenger RNAs that carry genetic material for making proteins and non-coding RNAs that function in varied cellular processes. In addition, active RNA degradation systems are the first defense against RNA viruses and provide the underlying machinery for more advanced cellular immune strategies such as RNAi. Some cells also secrete copious quantities of non-specific RN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNase H
Ribonuclease H (abbreviated RNase H or RNH) is a family of non-sequence-specific endonuclease enzymes that catalyze the cleavage of RNA in an RNA/ DNA substrate via a hydrolytic mechanism. Members of the RNase H family can be found in nearly all organisms, from bacteria to archaea to eukaryotes. The family is divided into evolutionarily related groups with slightly different substrate preferences, broadly designated ribonuclease H1 and H2. The human genome encodes both H1 and H2. Human ribonuclease H2 is a heterotrimeric complex composed of three subunits, mutations in any of which are among the genetic causes of a rare disease known as Aicardi–Goutières syndrome. A third type, closely related to H2, is found only in a few prokaryotes, whereas H1 and H2 occur in all domains of life. Additionally, RNase H1-like retroviral ribonuclease H domains occur in multidomain reverse transcriptase proteins, which are encoded by retroviruses such as HIV and are required for viral repl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNase A
Pancreatic ribonuclease family (, ''RNase'', ''RNase I'', ''RNase A'', ''pancreatic RNase'', ''ribonuclease I'', ''endoribonuclease I'', ''ribonucleic phosphatase'', ''alkaline ribonuclease'', ''ribonuclease'', ''gene S glycoproteins'', ''Ceratitis capitata alkaline ribonuclease'', ''SLSG glycoproteins'', ''gene S locus-specific glycoproteins'', ''S-genotype-assocd. glycoproteins'', ''ribonucleate 3'-pyrimidino-oligonucleotidohydrolase'') is a superfamily of pyrimidine-specific endonucleases found in high quantity in the pancreas of certain mammals and of some reptiles. Specifically, the enzymes are involved in endonucleolytic cleavage of 3'-phosphomononucleotides and 3'-phosphooligonucleotides ending in C-P or U-P with 2',3'-cyclic phosphate intermediates. Ribonuclease can unwind the RNA helix by complexing with single-stranded RNA; the complex arises by an extended multi-site cation-anion interaction between lysine and arginine residues of the enzyme and phosphate groups of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNase L
Ribonuclease L or RNase L (for ''latent''), known sometimes as ribonuclease 4 or 2'-5' oligoadenylate synthetase-dependent ribonuclease — is an interferon (IFN)-induced ribonuclease which, upon activation, destroys all RNA within the cell (both cellular and viral). RNase L is an enzyme that in humans is encoded by the ''RNASEL'' gene. This gene encodes a component of the interferon-regulated 2'-5'oligoadenylate (2'-5'A) system that functions in the antiviral and antiproliferative roles of interferons. RNase L is activated by dimerization, which occurs upon 2'-5'A binding, and results in cleavage of all RNA in the cell. This can lead to activation of MDA5, an RNA helicase involved in the production of interferons. Synthesis and activation RNase L is present in very minute quantities during the normal cell cycle. When interferon binds to cell receptors, it activates transcription of around 300 genes to bring about the antiviral state. Among the enzymes produced is RNase L, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribonuclease A
Pancreatic ribonuclease family (, ''RNase'', ''RNase I'', ''RNase A'', ''pancreatic RNase'', ''ribonuclease I'', ''endoribonuclease I'', ''ribonucleic phosphatase'', ''alkaline ribonuclease'', ''ribonuclease'', ''gene S glycoproteins'', ''Ceratitis capitata alkaline ribonuclease'', ''SLSG glycoproteins'', ''gene S locus-specific glycoproteins'', ''S-genotype-assocd. glycoproteins'', ''ribonucleate 3'-pyrimidino-oligonucleotidohydrolase'') is a superfamily of pyrimidine-specific endonucleases found in high quantity in the pancreas of certain mammals and of some reptiles. Specifically, the enzymes are involved in endonucleolytic cleavage of 3'-phosphomononucleotides and 3'-phosphooligonucleotides ending in C-P or U-P with 2',3'-cyclic phosphate intermediates. Ribonuclease can unwind the RNA helix by complexing with single-stranded RNA; the complex arises by an extended multi-site cation-anion interaction between lysine and arginine residues of the enzyme and phosphate groups of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNase PhyM
RNase PhyM is a type of endoribonuclease An endoribonuclease is a ribonuclease endonuclease. It cleaves either single-stranded or double-stranded RNA, depending on the enzyme. Example includes both single proteins such as RNase III, RNase A, RNase T1, RNase T2 and RNase H and also com ... which is sequence specific for single stranded RNAs. It cleaves 3'-end of unpaired A and U residues. External links * * Ribonucleases {{Hydrolase-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNase P
Ribonuclease P (, ''RNase P'') is a type of ribonuclease which cleaves RNA. RNase P is unique from other RNases in that it is a ribozyme – a ribonucleic acid that acts as a catalyst in the same way that a protein-based enzyme would. Its function is to cleave off an extra, or precursor, sequence of RNA on tRNA molecules. Further, RNase P is one of two known multiple turnover ribozymes in nature (the other being the ribosome), the discovery of which earned Sidney Altman and Thomas Cech the Nobel Prize in Chemistry in 1989: in the 1970s, Altman discovered the existence of precursor tRNA with flanking sequences and was the first to characterize RNase P and its activity in processing of the 5' leader sequence of precursor tRNA. Recent findings also reveal that RNase P has a new function. It has been shown that human nuclear RNase P is required for the normal and efficient transcription of various small noncoding RNAs, such as tRNA, 5S rRNA, SRP RNA and U6 snRNA genes, which a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exoribonuclease
An exoribonuclease is an exonuclease ribonuclease, which are enzymes that degrade RNA by removing terminal nucleotides from either the 5' end or the 3' end of the RNA molecule. Enzymes that remove nucleotides from the 5' end are called ''5'-3' exoribonucleases'', and enzymes that remove nucleotides from the 3' end are called ''3'-5' exoribonucleases''. Exoribonucleases can use either water to cleave the nucleotide-nucleotide bond (which is called hydrolytic activity) or inorganic phosphate (which is called phosphorolytic activity). Hydrolytic exoribonucleases are classified under EC number 3.1 and phosphorolytic exoribonucleases under EC number 2.7.7. As the phosphorolytic enzymes use inorganic phosphate to cleave bonds they release nucleotide diphosphates, whereas the hydrolytic enzymes (which use water) release nucleotide monosphosphates. Exoribonucleases exist in all kingdoms of life, the bacteria, archaea, and eukaryotes. Exoribonucleases are involved in the degradation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNase III
Ribonuclease III (RNase III or RNase C)(BREND3.1.26.3 is a type of ribonuclease that recognizes dsRNA and cleaves it at specific targeted locations to transform them into mature RNAs. These enzymes are a group of endoribonucleases that are characterized by their ribonuclease domain, which is labelled the RNase III domain. They are ubiquitous compounds in the cell and play a major role in pathways such as RNA precursor synthesis, RNA Silencing, and the ''pnp'' autoregulatory mechanism. Types of RNase III The RNase III superfamily is divided into four known classes: 1, 2, 3, and 4. Each class is defined by its domain structure.Liang Y-H, Lavoie M, Comeau M-A, Elela SA, Ji X. Structure of a Eukaryotic RNase III Post-Cleavage Complex Reveals a Double- Ruler Mechanism for Substrate Selection. Molecular cell. 2014;54(3):431-444. doi:10.1016/j.molcel.2014.03.006. Class 1 RNase III *Class 1 RNase III enzymes have a homodimeric structure whose function is to cleave dsRNA into multiple s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endoribonuclease
An endoribonuclease is a ribonuclease endonuclease. It cleaves either single-stranded or double-stranded RNA, depending on the enzyme. Example includes both single proteins such as RNase III, RNase A, RNase T1, RNase T2 and RNase H and also complexes of proteins with RNA such as RNase P and the RNA-induced silencing complex. Further examples include endoribonuclease XendoU found in frogs (''Xenopus ''Xenopus'' () (Gk., ξενος, ''xenos''=strange, πους, ''pous''=foot, commonly known as the clawed frog) is a genus of highly aquatic frogs native to sub-Saharan Africa. Twenty species are currently described within it. The two best-known ...''). External links * {{Nucleases EC 3.1 Ribonucleases ... [...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 residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribosome
Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) 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 (rRNA) molecules and many ribosomal proteins (RPs or r-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 chain. Ribosomes bind to messenger RNAs and use their sequences for determining the correct sequence of amino acids to generate a given protein. Amino acids are selected and carried to the ribosome by transfer RNA (tRNA) molecules, which enter the ribosome and bind to the messenger RNA chain via an anti-c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
