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:''Pol III can also refer to HNoMS Pol III, a Norwegian guard vessel from WWII'' 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 correct replication mistakes by means of exonuclease activity working 3'→5'. 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 (encoded by the dnaE gene) has the polymerase activity. * *the ε subunit (dnaQ) has 3'→5' exonuclease activity. * *the θ subunit (holE) stimulates the ε subunit's proofreading. *2 β units (dnaN) which act as sliding DNA clamps, they keep the polymerase bound to the DNA. *2 τ units (dnaX) which acts to dimerize two of the core enzymes (α, ε, and θ subunits). *1 γ unit (also dnaX) which acts as a clamp loader for the lagging strand Okazaki fragments, helping the two β subunits to form a unit and bind to DNA. The γ unit is made up of 5 γ subunits which include 3 γ subunits, 1 δ subunit (holA), and 1 δ' subunit (holB). The δ is involved in copying of the lagging strand. * Χ (holC) and Ψ (holD) which form a 1:1 complex and bind to γ or τ. X can also mediate the switch from RNA primer to DNA. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「DNA polymerase III holoenzyme」の詳細全文を読む スポンサード リンク
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