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AlkD Recognizes DNA
AlkD (Alkylpurine glycosylase D) is an enzyme belonging to a family of DNA glycosylases that are involved in DNA repair. It was discovered by a team of Norwegian biologists from Oslo in 2006. It was isolated from a soil-dwelling Gram-positive bacteria '' Bacillus cereus'', along with another enzyme AlkC. AlkC and AlkD are most probably derived from the same protein as indicated by their close resemblance. They are also found in other prokaryotes. Among eukaryotes, they are found only in the single-celled species only, such as '' Entamoeba histolytica'' and '' Dictyostelium discoideum''. The enzyme specifically targets 7mG (methyl-guanine) in the DNA, and is, therefore, unique among DNA glycosylases. It can also act on other methylpurines with less affinity. It indicates that the enzyme is specific for locating and cutting ( excision) of chemically modified bases from DNA, exactly at 7mG, whenever there are errors in replication. It accelerates the rate of 7mG hydrolysis 100-fold o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AlkD With DNA
AlkD (Alkylpurine glycosylase D) is an enzyme belonging to a family of DNA glycosylases that are involved in DNA repair. It was discovered by a team of Norwegian biologists from Oslo in 2006. It was isolated from a soil-dwelling Gram-positive bacteria '' Bacillus cereus'', along with another enzyme AlkC. AlkC and AlkD are most probably derived from the same protein as indicated by their close resemblance. They are also found in other prokaryotes. Among eukaryotes, they are found only in the single-celled species only, such as '' Entamoeba histolytica'' and '' Dictyostelium discoideum''. The enzyme specifically targets 7mG (methyl-guanine) in the DNA, and is, therefore, unique among DNA glycosylases. It can also act on other methylpurines with less affinity. It indicates that the enzyme is specific for locating and cutting ( excision) of chemically modified bases from DNA, exactly at 7mG, whenever there are errors in replication. It accelerates the rate of 7mG hydrolysis 100-fold o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Replication
In molecular biology, DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA replication occurs in all living organisms acting as the most essential part for biological inheritance. This is essential for cell division during growth and repair of damaged tissues, while it also ensures that each of the new cells receives its own copy of the DNA. The cell possesses the distinctive property of division, which makes replication of DNA essential. DNA is made up of a double helix of two complementary strands. The double helix describes the appearance of a double-stranded DNA which is thus composed of two linear strands that run opposite to each other and twist together to form. During replication, these strands are separated. Each strand of the original DNA molecule then serves as a template for the production of its counterpart, a process referred to as semiconservative replication. As a result of semi-conservative rep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleic Acid Structure
Nucleic acid structure refers to the structure of nucleic acids such as DNA and RNA. Chemically speaking, DNA and RNA are very similar. Nucleic acid structure is often divided into four different levels: primary, secondary, tertiary, and quaternary. Primary structure Primary structure consists of a linear sequence of nucleotides that are linked together by phosphodiester bond. It is this linear sequence of nucleotides that make up the primary structure of DNA or RNA. Nucleotides consist of 3 components: # Nitrogenous base ## Adenine ## Guanine ## Cytosine ## Thymine (present in DNA only) ## Uracil (present in RNA only) # 5-carbon sugar which is called deoxyribose (found in DNA) and ribose (found in RNA). # One or more phosphate groups. The nitrogen bases adenine and guanine are purine in structure and form a glycosidic bond between their 9 nitrogen and the 1' -OH group of the deoxyribose. Cytosine, thymine, and uracil are pyrimidines, hence the glycosidic bonds form betwee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkylation
Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effecting alkylation. Alkyl groups can also be removed in a process known as dealkylation. Alkylating agents are often classified according to their nucleophilic or electrophilic character. In oil refining contexts, alkylation refers to a particular alkylation of isobutane with olefins. For upgrading of petroleum, alkylation produces a premium blending stock for gasoline. In medicine, alkylation of DNA is used in chemotherapy to damage the DNA of cancer cells. Alkylation is accomplished with the class of drugs called alkylating antineoplastic agents. Nucleophilic alkylating agents Nucleophilic alkylating agents deliver the equivalent of an alkyl anion ( carbanion). The formal "alkyl anion" attacks an electrophile, forming a new covalent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aromaticity
In chemistry, aromaticity is a chemical property of cyclic ( ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to saturated compounds having single bonds, and other geometric or connective non-cyclic arrangements with the same set of atoms. Aromatic rings are very stable and do not break apart easily. Organic compounds that are not aromatic are classified as aliphatic compounds—they might be cyclic, but only aromatic rings have enhanced stability. The term ''aromaticity'' with this meaning is historically related to the concept of having an aroma, but is a distinct property from that meaning. Since the most common aromatic compounds are derivatives of benzene (an aromatic hydrocarbon common in petroleum and its distillates), the word ''aromatic'' occasionally refers informally to benzene derivatives, and so it was first defined. Nevertheless, many non-be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helix
A helix () is a shape like a corkscrew or spiral staircase. It is a type of smooth space curve with tangent lines at a constant angle to a fixed axis. Helices are important in biology, as the DNA molecule is formed as two intertwined helices, and many proteins have helical substructures, known as alpha helices. The word ''helix'' comes from the Greek word ''ἕλιξ'', "twisted, curved". A "filled-in" helix – for example, a "spiral" (helical) ramp – is a surface called ''helicoid''. Properties and types The ''pitch'' of a helix is the height of one complete helix turn, measured parallel to the axis of the helix. A double helix consists of two (typically congruent) helices with the same axis, differing by a translation along the axis. A circular helix (i.e. one with constant radius) has constant band curvature and constant torsion. A ''conic helix'', also known as a ''conic spiral'', may be defined as a spiral on a conic surface, with the distance to the apex an expo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Mass Unit
The dalton or unified atomic mass unit (symbols: Da or u) is a non-SI unit of mass widely used in physics and chemistry. It is defined as of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest. The atomic mass constant, denoted ''m''u, is defined identically, giving . This unit is commonly used in physics and chemistry to express the mass of atomic-scale objects, such as atoms, molecules, and elementary particles, both for discrete instances and multiple types of ensemble averages. For example, an atom of helium-4 has a mass of . This is an intrinsic property of the isotope and all helium-4 atoms have the same mass. Acetylsalicylic acid (aspirin), , has an average mass of approximately . However, there are no acetylsalicylic acid molecules with this mass. The two most common masses of individual acetylsalicylic acid molecules are , having the most common isotopes, and , in which one carbon is carbon-13. The molecular mass ... [...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] |
AlkD Recognizes DNA
AlkD (Alkylpurine glycosylase D) is an enzyme belonging to a family of DNA glycosylases that are involved in DNA repair. It was discovered by a team of Norwegian biologists from Oslo in 2006. It was isolated from a soil-dwelling Gram-positive bacteria '' Bacillus cereus'', along with another enzyme AlkC. AlkC and AlkD are most probably derived from the same protein as indicated by their close resemblance. They are also found in other prokaryotes. Among eukaryotes, they are found only in the single-celled species only, such as '' Entamoeba histolytica'' and '' Dictyostelium discoideum''. The enzyme specifically targets 7mG (methyl-guanine) in the DNA, and is, therefore, unique among DNA glycosylases. It can also act on other methylpurines with less affinity. It indicates that the enzyme is specific for locating and cutting ( excision) of chemically modified bases from DNA, exactly at 7mG, whenever there are errors in replication. It accelerates the rate of 7mG hydrolysis 100-fold o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleic Acid
Nucleic acids are biopolymers, macromolecules, essential to all known forms of life. They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main classes of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). If the sugar is ribose, the polymer is RNA; if the sugar is the ribose derivative deoxyribose, the polymer is DNA. Nucleic acids are naturally occurring chemical compounds that serve as the primary information-carrying molecules in cells and make up the genetic material. Nucleic acids are found in abundance in all living things, where they create, encode, and then store information of every living cell of every life-form on Earth. In turn, they function to transmit and express that information inside and outside the cell nucleus to the interior operations of the cell and ultimately to the next generation of each living organism. The encoded information is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HEAT Repeat Domain
A HEAT repeat is a protein tandem repeat structural motif composed of two alpha helices linked by a short loop. HEAT repeats can form alpha solenoids, a type of solenoid protein domain found in a number of cytoplasmic proteins. The name "HEAT" is an acronym for four proteins in which this repeat structure is found: Huntingtin, elongation factor 3 (EF3), protein phosphatase 2A (PP2A), and the yeast kinase TOR1. HEAT repeats form extended superhelical structures which are often involved in intracellular transport; they are structurally related to armadillo repeats. The nuclear transport protein importin beta contains 19 HEAT repeats. Various HEAT repeat proteins and their structures Representative examples of HEAT repeat proteins include importin β (also known as karyopherin β) family, regulatory subunits of condensin and cohesin, separase, PIKKs (phosphatidylinositol 3-kinase-related protein kinases) such as ATM ( Ataxia telangiectasia mutated) and ATR (Ataxia telangiectasia an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystal Structure
In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystal, crystalline material. Ordered structures occur from the intrinsic nature of the constituent particles to form symmetric patterns that repeat along the principal directions of Three-dimensional space (mathematics), three-dimensional space in matter. The smallest group of particles in the material that constitutes this repeating pattern is the unit cell of the structure. The unit cell completely reflects the symmetry and structure of the entire crystal, which is built up by repetitive Translation (geometry), translation of the unit cell along its principal axes. The translation vectors define the nodes of the Bravais lattice. The lengths of the principal axes, or edges, of the unit cell and the angles between them are the lattice constants, also called ''lattice parameters'' or ''cell parameters''. The symmetry properties of the crystal are described by the con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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