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In order to protect the bacterial genomic DNA from its own restriction enzymes, bacterial cells employ a system, wherein methyl transferases methylate certain bases on the DNA sequence, making them unrecognizable to the restriction enzymes.
Each restriction enzyme has a methylase associated with it on the chromosome. This methylase puts methyl groups on the host DNA, and the restriction enzyme doesn't recognize its recognition sequence when it is so methlyated. The host DNA is thus protected from the actions of its own restriction enzyme.
Incoming (foreign) DNA is unlikely to be protected (methylated) in the same manner, thus this invading DNA is digested by the hosts restriction enzyme(s).
When working in cloning experiments, the principle is the same -- DNA to be digested is carried by a plasmid in a host that does not methylate DNA in the pattern that would cause the restriction enzyme to see it as protected, thus it is cut. DNA generated by PCR is similarly unmethylated, and is therefore also digested.
Some enzymes won't cut DNA isolated from dam+ or dcm+ hosts (two common bacterial methylases), thus one must know the genotype of the host cloning strain if using a restriction enzyme whose action is blocked by dam ordcmmethylation.
What else can I help you with?
How do restriction enzymes determine the specific location to cleave DNA molecules during the process of genetic modification?
Restriction enzymes recognize specific sequences of nucleotides in DNA molecules called recognition sites. These enzymes bind to these sites and cleave the DNA at specific locations, allowing for precise genetic modification.
Is topoisomerases belong to restriction enzymes?
No, topoisomerases are not the same as restriction enzymes. Topoisomerases are enzymes that regulate the supercoiling of DNA, while restriction enzymes recognize specific DNA sequences and cleave them. Both enzymes play different roles in DNA metabolism.
What are enzymes cutting DNA at specific sites to form restriction fragments called?
Enzymes that cut DNA at specific sites to form restriction fragments are called restriction endonucleases or restriction enzymes. These enzymes recognize specific DNA sequences and cleave the DNA at or near these sequences, generating DNA fragments with defined ends.
What is used to cut the DNA chain so that new genes may be inserted?
Enzymes called restriction endonucleases are used to cut the DNA chain at specific recognition sites. These enzymes recognize and cleave the DNA at particular sequences, allowing new genes to be inserted at the site of the cut.
What is the substance required to cleave the vector DNA during recombinant DNA technology?
Restriction enzymes are the substances required to cleave the vector DNA during recombinant DNA technology. These enzymes recognize specific DNA sequences and cut the DNA at specific points, allowing for the insertion of foreign DNA fragments.
What is the difference between Restriction endonucleases and exonucleases?
Exonuclease enzymes cleave nucleotides from the ends of DNA molecules. Endonuclease enzymes cleave a phosphodiester bond somewhere within the DNA molecule (not at the ends).
What are used to cleave DNA into fragments?
Restriction enzymes. Babe
How can bacterium produce restriction enzymes that do not cleave it's DNA?
Restriction enzymes cleave DNA at a particular recognition site -- a particular sequence of nucleotides. You can imagine the following scenarios:1. The bacterial chromosome does not contain the recognition sequence2. The bacterial chromosome contains the recognition sequence, but that particular part of the DNA is either supercoiled to keep the restriction enzyme from finding the sequence, or it's single stranded as when being replicated or transcribed.3. The bacterial chromosome contains the recognition sequence, but that particular part of the DNA is methylated or modified in some other way which prevents the restriction enzyme from attaching.
Can virus get a bacteria?
Yes- Bacterial viruses are called bacteriophages. Some examples are T4 and T7 phages. They are complex DNA viruses that attach themselves to the cell surface and then inject their DNA to the inside of the bacteria. Bacteria have enzymes called restriction enzymes that cleave DNA at specific sites called restriction sites. These enzymes are the bacterium's defense against phages.
Do restriction enzymes cut protein molecules at specific sites?
No, restriction enzymes cut DNA molecules at specific sites. They recognize specific sequences of nucleotides in DNA and cleave the phosphate backbone at those points. Proteins are not typically cut by restriction enzymes.
How do restriction enzymes determine the specific location to cleave DNA molecules during the process of genetic modification?
Restriction enzymes recognize specific sequences of nucleotides in DNA molecules called recognition sites. These enzymes bind to these sites and cleave the DNA at specific locations, allowing for precise genetic modification.
Is topoisomerases belong to restriction enzymes?
No, topoisomerases are not the same as restriction enzymes. Topoisomerases are enzymes that regulate the supercoiling of DNA, while restriction enzymes recognize specific DNA sequences and cleave them. Both enzymes play different roles in DNA metabolism.
What are enzymes cutting DNA at specific sites to form restriction fragments called?
Enzymes that cut DNA at specific sites to form restriction fragments are called restriction endonucleases or restriction enzymes. These enzymes recognize specific DNA sequences and cleave the DNA at or near these sequences, generating DNA fragments with defined ends.
Where restriction enzymes come from?
Restriction enzyme, also called restriction endonuclease, a protein produced by bacteria that cleaves DNA at specific sites along the molecule. In the bacterial cell, restriction enzymes cleave foreign DNA, thus eliminating infecting organisms.
What is used to cut the DNA chain so that new genes may be inserted?
Enzymes called restriction endonucleases are used to cut the DNA chain at specific recognition sites. These enzymes recognize and cleave the DNA at particular sequences, allowing new genes to be inserted at the site of the cut.
What is the substance required to cleave the vector DNA during recombinant DNA technology?
Restriction enzymes are the substances required to cleave the vector DNA during recombinant DNA technology. These enzymes recognize specific DNA sequences and cut the DNA at specific points, allowing for the insertion of foreign DNA fragments.
What is the relationship between restriction sites and a restriction map?
Restriction sites are specific sequences in a DNA molecule where restriction enzymes can bind and cleave the DNA. A restriction map is a diagram that shows the locations of these restriction sites along a DNA sequence. The map provides information on the sizes of the resulting DNA fragments after digestion with different restriction enzymes.
