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DNA Polymerase III Holoenzyme
DNA polymerase III holoenzyme is the primary enzyme complex involved in prokaryotic DNA replication. It was discovered by Thomas Kornberg (son of Arthur Kornberg) and Malcolm Gefter in 1970. The complex has high processivity (i.e. the number of nucleotides added per binding event) and, specifically referring to the replication of the '' E.coli'' genome, works in conjunction with four other DNA polymerases (Pol I, Pol II, Pol IV, and Pol V). Being the primary holoenzyme involved in replication activity, the DNA Pol III holoenzyme also has proofreading capabilities that corrects replication mistakes by means of exonuclease activity reading 3'→5' and synthesizing 5'→3'. DNA Pol III is a component of the replisome, which is located at the replication fork. Components The replisome is composed of the following: *2 DNA Pol III enzymes, each comprising α, ε and θ subunits. (It has been proven that there is a third copy of Pol III at the replisome.) **the α subunit (encode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Polymerase III (with Subunits)
DNA polymerase III holoenzyme is the primary enzyme complex involved in prokaryotic DNA replication. It was discovered by Thomas B. Kornberg, Thomas Kornberg (son of Arthur Kornberg) and Malcolm Gefter in 1970. The complex has high processivity (i.e. the number of nucleotides added per binding event) and, specifically referring to the replication of the ''Escherichia coli, E.coli'' genome, works in conjunction with four other DNA polymerases (Pol I, Pol II, Pol IV, and Pol V). Being the primary holoenzyme involved in replication activity, the DNA Pol III holoenzyme also has proofreading capabilities that corrects replication mistakes by means of exonuclease activity reading 3'→5' and synthesizing 5'→3'. DNA Pol III is a component of the replisome, which is located at the replication fork. Components The replisome is composed of the following: *2 DNA Pol III enzymes, each comprising α, ε and θ subunits. (It has been proven that there is a third copy of Pol III at the repl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DnaE
DnaE, the gene product of ''dnaE'', is the catalytic α subunit of DNA polymerase III, acting as a DNA polymerase. This enzyme is only found in prokaryotes A prokaryote () is a single-celled organism that lacks a nucleus and other membrane-bound organelles. The word ''prokaryote'' comes from the Greek πρό (, 'before') and κάρυον (, 'nut' or 'kernel').Campbell, N. "Biology:Concepts & Connec .... References Bacterial proteins DNA replication {{molecular-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNA Polymerase
In molecular biology, RNA polymerase (abbreviated RNAP or RNApol), or more specifically DNA-directed/dependent RNA polymerase (DdRP), is an enzyme that synthesizes RNA from a DNA template. Using the enzyme helicase, RNAP locally opens the double-stranded DNA so that one strand of the exposed nucleotides can be used as a template for the synthesis of RNA, a process called transcription. A transcription factor and its associated transcription mediator complex must be attached to a DNA binding site called a promoter region before RNAP can initiate the DNA unwinding at that position. RNAP not only initiates RNA transcription, it also guides the nucleotides into position, facilitates attachment and elongation, has intrinsic proofreading and replacement capabilities, and termination recognition capability. In eukaryotes, RNAP can build chains as long as 2.4 million nucleotides. RNAP produces RNA that, functionally, is either for protein coding, i.e. messenger RNA (mRNA); or n ... [...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] |
RNA Primer
Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in Genetic code, coding, Translation (biology), decoding, Regulatory RNA, regulation and Gene expression, expression of genes. RNA and deoxyribonucleic acid (DNA) are nucleic acids. Along with lipids, proteins, and carbohydrates, nucleic acids constitute one of the four major macromolecules essential for all known forms of life. Like DNA, RNA is assembled as a chain of nucleotides, but unlike DNA, RNA is found in nature as a single strand folded onto itself, rather than a paired double strand. Cellular organisms use messenger RNA (''mRNA'') to convey genetic information (using the nucleobase, nitrogenous bases of guanine, uracil, adenine, and cytosine, denoted by the letters G, U, A, and C) that directs synthesis of specific proteins. Many viruses encode their genetic information using an RNA genome. Some RNA molecules play an active role within cells by catalyzing biological reactions, control ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HolD
Hold may refer to: Physical spaces * Hold (ship), interior cargo space * Baggage hold, cargo space on an airplane * Stronghold, a castle or other fortified place Arts, entertainment, and media * Hold (musical term), a pause, also called a Fermata * "Hold" (song), a song by Vera Blue * "Hold", a song by Axium from '' Blindsided'' * "Hold", a song by Saves the Day from '' I'm Sorry I'm Leaving'' * Hold, in a card game (e.g., blackjack or poker, the cards that are kept in a hand, not those discarded and replaced * Handhold (dance), a type of hold in dance * Hold (novel) a novel by Michael Donkor Law * Legal hold, a legal ruling or official declaration * Secret hold, a parliamentary procedure Sports * Hold (baseball), a statistic that may be awarded to a relief pitcher * Climbing hold, on climbing walls * Grappling hold, a specific grip applied to an opponent in wrestling or martial arts Technology * Hold (aviation), a manoeuvre designed to delay an aircraft already in flight whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HolC
In ''E. coli'' and other bacteria, holC is a gene that encodes the chi subunit of DNA polymerase III DNA polymerase III holoenzyme is the primary enzyme complex involved in prokaryotic DNA replication. It was discovered by Thomas Kornberg (son of Arthur Kornberg) and Malcolm Gefter in 1970. The complex has high processivity (i.e. the number of .... References Bacterial proteins DNA replication {{molecular-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HolB
In ''E. coli'' and other bacteria, holB is a gene that encodes the delta prime subunit of DNA polymerase III DNA polymerase III holoenzyme is the primary enzyme complex involved in prokaryotic DNA replication. It was discovered by Thomas Kornberg (son of Arthur Kornberg) and Malcolm Gefter in 1970. The complex has high processivity (i.e. the number of .... References Bacterial proteins DNA replication {{molecular-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HolA
In molecular biology, the δ (delta) subunit of DNA polymerase III is encoded by the holA gene in ''E. coli'' and other bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among .... Along with the γ, δ', χ, and ψ subunits that make up the core polymerase, and the β accessory proteins, the δ subunit is responsible for the high speed and processivity of polIII. References {{DNA replication Bacterial proteins Protein families DNA replication ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Okazaki Fragment
Okazaki fragments are short sequences of DNA nucleotides (approximately 150 to 200 base pairs long in eukaryotes) which are synthesized discontinuously and later linked together by the enzyme DNA ligase to create the lagging strand during DNA replication. They were discovered in the 1960s by the Japanese molecular biologists Reiji and Tsuneko Okazaki, along with the help of some of their colleagues. During DNA replication, the double helix is unwound and the complementary strands are separated by the enzyme DNA helicase, creating what is known as the DNA replication fork. Following this fork, DNA primase and DNA polymerase begin to act in order to create a new complementary strand. Because these enzymes can only work in the 5’ to 3’ direction, the two unwound template strands are replicated in different ways. One strand, the leading strand, undergoes a continuous replication process since its template strand has 3’ to 5’ directionality, allowing the polymerase assembl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DnaX
The τ and γ subunits are part of the DNA polymerase III holoenzyme of prokaryotes. The protein family is characterized by the well-conserved first N-terminal domain, approx. 365 amino acids. The eukaryotic equivalent to the DNA clamp loader is replication factor C, with the subunits RFC1, RFC2, RFC3, RFC4, and RFC5 Replication factor C subunit 5 is a protein that in humans is encoded by the ''RFC5'' gene. Function The elongation of primed DNA templates by DNA polymerase delta and DNA polymerase epsilon requires the accessory proteins proliferating cell .... The domain is also found in plants as gene STICHEL (STI), with similarity to cyanobacterial sequences. However, STI in plants is nuclear-localized and does not participate in genome duplication. It seems to instead regulate branching. References Bacterial proteins Protein families DNA replication {{molecular-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Clamp
A DNA clamp, also known as a sliding clamp, is a protein complex that serves as a processivity-promoting factor in DNA replication. As a critical component of the DNA polymerase III holoenzyme, the clamp protein binds DNA polymerase and prevents this enzyme from dissociating from the template DNA strand. The clamp-polymerase protein–protein interactions are stronger and more specific than the direct interactions between the polymerase and the template DNA strand; because one of the rate-limiting steps in the DNA synthesis reaction is the association of the polymerase with the DNA template, the presence of the sliding clamp dramatically increases the number of nucleotides that the polymerase can add to the growing strand per association event. The presence of the DNA clamp can increase the rate of DNA synthesis up to 1,000-fold compared with a nonprocessive polymerase. Structure The DNA clamp is an alpha+beta protein fold, α+β protein that assembles into a multimeric, six-d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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