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DnaG
DnaG is a bacterial DNA primase and is encoded by the ''dnaG'' gene. The enzyme DnaG, and any other DNA primase, synthesizes short strands of RNA known as oligonucleotides during DNA replication. These oligonucleotides are known as primers because they act as a starting point for DNA synthesis. DnaG catalyzes the synthesis of oligonucleotides that are 10 to 60 nucleotides (the fundamental unit of DNA and RNA) long, however most of the oligonucleotides synthesized are 11 nucleotides. These RNA oligonucleotides serve as primers, or starting points, for DNA synthesis by bacterial DNA polymerase III (Pol III). DnaG is important in bacterial DNA replication because DNA polymerase cannot initiate the synthesis of a DNA strand, but can only add nucleotides to a preexisting strand. DnaG synthesizes a single RNA primer at the origin of replication. This primer serves to prime leading strand DNA synthesis. For the other parental strand, the lagging strand, DnaG synthesizes an RNA prime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DnaG Zinc Binding Domain
DnaG is a bacterial DNA primase and is encoded by the ''dnaG'' gene. The enzyme DnaG, and any other DNA primase, synthesizes short strands of RNA known as oligonucleotides during DNA replication. These oligonucleotides are known as primers because they act as a starting point for DNA synthesis. DnaG catalyzes the synthesis of oligonucleotides that are 10 to 60 nucleotides (the fundamental unit of DNA and RNA) long, however most of the oligonucleotides synthesized are 11 nucleotides. These RNA oligonucleotides serve as primers, or starting points, for DNA synthesis by bacterial DNA polymerase III (Pol III). DnaG is important in bacterial DNA replication because DNA polymerase cannot initiate the synthesis of a DNA strand, but can only add nucleotides to a preexisting strand. DnaG synthesizes a single RNA primer at the origin of replication. This primer serves to prime leading strand DNA synthesis. For the other parental strand, the lagging strand, DnaG synthesizes an RNA prime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primase
DNA primase is an enzyme involved in the replication of DNA and is a type of RNA polymerase. Primase catalyzes the synthesis of a short RNA (or DNA in some living organisms) segment called a primer complementary to a ssDNA (single-stranded DNA) template. After this elongation, the RNA piece is removed by a 5' to 3' exonuclease and refilled with DNA. Function In bacteria, primase binds to the DNA helicase forming a complex called the primosome. Primase is activated by the helicase where it then synthesizes a short RNA primer approximately 11 ±1 nucleotides long, to which new nucleotides can be added by DNA polymerase. Archaeal and eukaryote primases are heterodimeric proteins with one large regulatory and one minuscule catalytic subunit. The RNA segments are first synthesized by primase and then elongated by DNA polymerase. Then the DNA polymerase forms a protein complex with two primase subunits to form the alpha DNA Polymerase primase complex. Primase is one of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leading Strand
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 repl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagging Strand
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 repl ... [...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] |
Primosome
In molecular biology, a primosome is a protein complex responsible for creating RNA primers on single stranded DNA during DNA replication. The primosome consists of seven proteins: DnaG primase, DnaB helicase, DnaC helicase assistant, DnaT, PriA, Pri B, and PriC. At each replication fork, the primosome is utilized once on the leading strand of DNA and repeatedly, initiating each Okazaki fragment, on the lagging DNA strand. Initially the complex formed by PriA, PriB, and PriC binds to DNA. Then the DnaB-DnaC helicase complex attaches along with DnaT. This structure is referred to as the pre-primosome. Finally, DnaG will bind to the pre-primosome forming a complete primosome. The primosome attaches 1-10 RNA nucleotides to the single stranded DNA creating a DNA-RNA hybrid. This sequence of RNA is used as a primer to initiate DNA polymerase III. The RNA bases are ultimately replaced with DNA bases by RNase H nuclease (eukaryotes) or DNA polymerase I nuclease (prokaryotes) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Replication Fork
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] |
Nucleoside Triphosphate
A nucleoside triphosphate is a nucleoside containing a nitrogenous base bound to a 5-carbon sugar (either ribose or deoxyribose), with three phosphate groups bound to the sugar. They are the molecular precursors of both DNA and RNA, which are chains of nucleotides made through the processes of DNA replication and transcription. Nucleoside triphosphates also serve as a source of energy for cellular reactions and are involved in signalling pathways. Nucleoside triphosphates cannot be absorbed well, so they are typically synthesized within the cell. Synthesis pathways differ depending on the specific nucleoside triphosphate being made, but given the many important roles of nucleoside triphosphates, synthesis is tightly regulated in all cases. Nucleoside analogues may also be used to treat viral infections. For example, azidothymidine (AZT) is a nucleoside analogue used to prevent and treat HIV/AIDS. Naming The term nucleoside refers to a nitrogenous base linked to a 5-carbon suga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base Pair
A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA and RNA. Dictated by specific hydrogen bonding patterns, "Watson–Crick" (or "Watson–Crick–Franklin") base pairs (guanine–cytosine and adenine–thymine) allow the DNA helix to maintain a regular helical structure that is subtly dependent on its nucleotide sequence. The Complementarity (molecular biology), complementary nature of this based-paired structure provides a redundant copy of the genetic information encoded within each strand of DNA. The regular structure and data redundancy provided by the DNA double helix make DNA well suited to the storage of genetic information, while base-pairing between DNA and incoming nucleotides provides the mechanism through which DNA polymerase replicates DNA and RNA polymerase transcribes DNA in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dehydration Synthesis
In chemistry, a dehydration reaction is a chemical reaction that involves the loss of water from the reacting molecule or ion. Dehydration reactions are common processes, the reverse of a hydration reaction. Dehydration reactions in organic chemistry Esterification The classic example of a dehydration reaction is the Fischer esterification, which involves treating a carboxylic acid with an alcohol to give an ester :RCO2H + R′OH RCO2R′ + H2O Often such reactions require the presence of a dehydrating agent, i.e. a substance that reacts with water. Etherification Two monosaccharides, such as glucose and fructose, can be joined together (to form saccharose) using dehydration synthesis. The new molecule, consisting of two monosaccharides, is called a disaccharide. Nitrile formation Nitriles are often prepared by dehydration of primary amides. :RC(O)NH2 → RCN + H2O Ketene formation Ketene is produced by heating acetic acid and trapping the product: :CH3CO2H → CH2=C= ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escherichia Coli
''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escherichia'' that is commonly found in the lower intestine of warm-blooded organisms. Most ''E. coli'' strains are harmless, but some serotypes ( EPEC, ETEC etc.) can cause serious food poisoning in their hosts, and are occasionally responsible for food contamination incidents that prompt product recalls. Most strains do not cause disease in humans and are part of the normal microbiota of the gut; such strains are harmless or even beneficial to humans (although these strains tend to be less studied than the pathogenic ones). For example, some strains of ''E. coli'' benefit their hosts by producing vitamin K2 or by preventing the colonization of the intestine by pathogenic bacteria. These mutually beneficial relationships between ''E. col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inorganic Pyrophosphatase
Inorganic pyrophosphatase (or inorganic diphosphatase, PPase) is an enzyme () that catalyzes the conversion of one ion of pyrophosphate to two phosphate ions. This is a highly exergonic reaction, and therefore can be coupled to unfavorable biochemical transformations in order to drive these transformations to completion. The functionality of this enzyme plays a critical role in lipid metabolism (including lipid synthesis and degradation), calcium absorption and bone formation, and DNA synthesis, as well as other biochemical transformations. Two types of inorganic diphosphatase, very different in terms of both amino acid sequence and structure, have been characterised to date: soluble and transmembrane proton-pumping pyrophosphatases (sPPases and H(+)-PPases, respectively). sPPases are ubiquitous proteins that hydrolyse pyrophosphate to release heat, whereas H+-PPases, so far unidentified in animal and fungal cells, couple the energy of PPi hydrolysis to proton movement across ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
