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Exoribonucleases
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 Enzyme Commission number, 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 Adenosine diphosphate, nucleotide diphosphates, whereas the hydrolytic enzymes (which use water) release Adenosine monophosphate, nucleotide monosphosphates. Exoribonucleases exist in all kingdoms of life, the bacteria, archa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exosome Complex
The exosome complex (or PM/Scl complex, often just called the exosome) is a multi-protein intracellular Protein complex, complex capable of degrading various types of RNA (ribonucleic acid) molecules. Exosome complexes are found in both eukaryotic cells and archaea, while in bacteria a simpler complex called the degradosome carries out similar functions. The core of the exosome contains a six-membered ring structure to which other proteins are attached. In eukaryotic cells, the exosome complex is present in the cytoplasm, Cell nucleus, nucleus, and especially the nucleolus, although different proteins interact with the exosome complex in these compartments regulating the RNA degradation activity of the complex to Substrate (biochemistry), substrates specific to these cell compartments. Substrates of the exosome include messenger RNA, ribosomal RNA, and many species of small RNAs. The exosome has an exoribonucleolytic function, meaning it degrades RNA starting at one end (the 3� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exosome Complex
The exosome complex (or PM/Scl complex, often just called the exosome) is a multi-protein intracellular Protein complex, complex capable of degrading various types of RNA (ribonucleic acid) molecules. Exosome complexes are found in both eukaryotic cells and archaea, while in bacteria a simpler complex called the degradosome carries out similar functions. The core of the exosome contains a six-membered ring structure to which other proteins are attached. In eukaryotic cells, the exosome complex is present in the cytoplasm, Cell nucleus, nucleus, and especially the nucleolus, although different proteins interact with the exosome complex in these compartments regulating the RNA degradation activity of the complex to Substrate (biochemistry), substrates specific to these cell compartments. Substrates of the exosome include messenger RNA, ribosomal RNA, and many species of small RNAs. The exosome has an exoribonucleolytic function, meaning it degrades RNA starting at one end (the 3� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3' RNA Degradation
Directionality, in molecular biology and biochemistry, is the end-to-end chemical orientation of a single strand of nucleic acid. In a single strand of DNA or RNA, the chemical convention of naming carbon atoms in the nucleotide pentose-sugar-ring means that there will be a 5′ end (usually pronounced "five-prime end"), which frequently contains a phosphate group attached to the 5′ carbon of the ribose ring, and a 3′ end (usually pronounced "three-prime end"), which typically is unmodified from the ribose -OH substituent. In a DNA double helix, the strands run in opposite directions to permit base pairing between them, which is essential for replication or transcription of the encoded information. Nucleic acids can only be synthesized in vivo in the 5′-to-3′ direction, as the polymerases that assemble various types of new strands generally rely on the energy produced by breaking nucleoside triphosphate bonds to attach new nucleoside monophosphates to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNase D
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 ... [...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 ... [...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-know ...''). External links * {{Nucleases EC 3.1 Ribonucleases ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exoribonuclease II
Exoribonuclease II (, ''ribonuclease II'', ''ribonuclease Q'', ''BN ribonuclease'', ''Escherichia coli exo-RNase II'', ''RNase II'', ''exoribonuclease (misleading)'', ''5'-exoribonuclease'') is an enzyme. This enzyme catalyses the following chemical reaction : Exonucleolytic cleavage in the 3'- to 5'-direction to yield nucleoside 5'-phosphates This enzyme has preference for single-stranded RNA. See also * 5'-3' exoribonuclease 2 5'-3' Exoribonuclease 2 (XRN2) also known as Dhm1-like protein is an exoribonuclease enzyme that in humans is encoded by the ''XRN2'' gene. The human gene encoding XRN2 shares similarity with the mouse Dhm1 and the yeast's Dhp1 (''Schizosaccharo ... References External links * {{Portal bar, Biology, border=no EC 3.1.13 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exoribonuclease I
5′-3′ exoribonuclease 1 (Xrn1) is a protein that in humans is encoded by the XRN1 gene. Xrn1 hydrolyses RNA in the 5′ to 3′ direction. Function This gene encodes a member of the 5′-3′ exonuclease family. The encoded protein may be involved in replication-dependent histone mRNA degradation, and interacts directly with the enhancer of mRNA-decapping protein 4. In addition to mRNA metabolism, a similar protein in yeast has been implicated in a variety of nuclear and cytoplasmic functions, including transcription, translation, homologous recombination, meiosis, telomere maintenance, and microtubule assembly. Mutations in this gene are associated with osteosarcoma, suggesting that the encoded protein may also play a role in bone formation. Alternative splicing Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polynucleotide Phosphorylase
Polynucleotide Phosphorylase (PNPase) is a bifunctional enzyme with a phosphorolytic 3' to 5' exoribonuclease activity and a 3'-terminal oligonucleotide polymerase activity. That is, it dismantles the RNA chain starting at the 3' end and working toward the 5' end. It also synthesizes long, highly heteropolymeric tails ''in vivo''. It accounts for all of the observed residual polyadenylation in strains of ''Escherichia coli'' missing the normal polyadenylation enzyme. Discovered by Marianne Grunberg-Manago working in Severo Ochoa's lab in 1955, the RNA-polymerization activity of PNPase was initially believed to be responsible for DNA-dependent synthesis of messenger RNA, a notion that got disproved by the late 1950s. It is involved in mRNA processing and degradation in bacteria, plants, and animals. In humans, the enzyme is encoded by the gene. In its active form, the protein forms a ring structure consisting of three PNPase molecules. Each PNPase molecule consists of two RNas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNase BN
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligoribonuclease
Oligonucleotidase (, ''oligoribonuclease'') is an exoribonuclease derived from '' Flammulina velutipes''. This enzyme catalyses the following chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking ... : 3'-end directed exonucleolytic cleavage of viral RNA-DNA hybrid References External links * * EC 3.1.13 {{biochem-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNase T
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
