Video Transcript
From what microorganisms are
restriction enzymes most commonly obtained?
This question asks us about
restriction enzymes. Let’s review what restriction
enzymes are and how they can be used to manipulate DNA.
Restriction enzymes are useful
tools in biotechnology because they can be used to cut specific DNA sequences so
they can be combined in interesting ways. They were originally discovered as
a defense mechanism against viral infection in bacteria. Some viruses can infect bacterial
cells by first injecting their DNA into the cell. Once the viral DNA is in the cell,
the DNA can be transcribed and translated to form proteins for the virus. The DNA can also be copied. All of this is used to assemble
more viruses.
So, the bacterial cell basically
becomes a virus-producing factory. This continues until the cell is
filled up with so much virus that it eventually bursts. Now, the virus can go on to infect
other cells. Restriction enzymes were discovered
in bacteria as a defense against this kind of infection. These can bind to viral DNA and cut
it into pieces.
Bacterial DNA has special
modifications present so restriction enzymes don’t cleave bacterial DNA. Because the viral DNA is now
fragmented, it can’t be used to make a copy of itself or to make proteins for the
virus. This means that the virus isn’t
able to complete its lifecycle and the bacterial host cell is protected.
Therefore, to answer our question,
the microorganisms where restriction enzymes are most commonly obtained are
bacteria.
