What's the difference between DNA polymerase I and III

Discussion in 'DAT Discussions' started by ROCOCO8, Jan 12, 2012.

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  1. ROCOCO8

    ROCOCO8 5+ Year Member

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    I'm a little confused about this..
    What's the difference bw I and III? .I always thought E. coli/bacteria only have DNA poly III...?
     
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  3. Blue87Fiero

    Blue87Fiero 2+ Year Member

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    I don't know which ones E.Coli has for sure but I thought I, II, and III all came from E.Coli. I actually thought it went up to five. I think DNA III was the biggest DNA Pol I was unique because it could "proof read" in both directions 5' to 3' and 3' to 5'. I am not sure if I am right on this I might check tomorrow if I remember. I just finished genetics and I should know this.
     
  4. ROCOCO8

    ROCOCO8 5+ Year Member

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    Oh well that makes more sense... But which type of polym do humans use?
     
  5. Ferferi

    Ferferi 2+ Year Member

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    I wasn't sure about the answer so I googled it and this is what I got

    DNA Polymerase III - makes the chain in a 5 to 3 direction and it proofreads with a 3 to 5 exonuclease, so it goes both ways doing something different
    DNA Polymerase I - breaks down the RNA primer with a 5 to 3 exonuclease.
     
  6. Dotoday

    Dotoday 7+ Year Member

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    The Molecular bio nomenclature states that DNA Polymerase I, II, and III is used in procaryotes like E-Coli. Eucaryotes use DNA Polymerase alpha, beta, delta, epsilon.

    DNA Polymerase III is responsible for leading and the lagging strand synthesis in bacteria. DNA Polymerase I replaces RNA primer with the DNA strand.

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