Genetics as it applies to evolution, molecular biology, and medical aspects.

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Post by kikkid » Fri Oct 05, 2007 7:30 pm

Could someone tell me if this is correct:
Explain why E. coli's own DNA is not cut by the restriction endonuclease EcoRI?

A bacterium protects its own DNA from digestion using other enzymes that modify nucleotides in the recognition site on the host DNA. E.coli makes the restriction enzyme EcoRI and the methylating enzyme EcoRI methylase. The methylase modifies EcoRI sites in the bacteria’s
own genome to prevent it from being digested.

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Post by raghda » Sat Oct 06, 2007 12:32 am

the bacterium contain both of the 2 enzyems as it uses methylases to methylate cytosine bases of bacterial DNA at restriction site , so theDNA becomes resistant to the action of the restriction endonuclease
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Post by canalon » Sat Oct 06, 2007 2:41 am

So in short your answer is correct.

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any proof. (Ashley Montague)

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