Restriction Endonuclease: Enzyme that can cleave DNA at a
specific base-pair sequence of nucleotides.
Cleaving
Sticky Ends: Short single-stranded
overhang ends from cleavage.
Ready to be paired with new DNA
strands.
Restriction Enzyme cuts specific DNA sequence and is added to another DNA gene in a plasmid. The plasmid
can then be injected into a bacterial cell and reproduce more genes, known as “recombinant DNA.”
Blunt Ends: Fully based paired ends
from cleavage. Not ready to bind with
new DNA strands.
Types
Type I: Cuts random sequences
Type II: Cuts specific areas close to or within
recognition sequence - most commonly used
Type IIS: Cleaves outside recognition sequence to one
side. Used on DNA with multiple recognition sites.
Type IIG: Cleaves outside recognition sequence and can
switch between cleaving other DNA and protecting
(methylase) own DNA
Type III: Cleaves outside recognition sequence and can
switch between cleaving other DNA and protecting (methylase)
own DNA
Type IV: Recognizes and cleaves modified
DNA
Applications
Genetic Engineering: Molecular Biologists target sequences
then isolate and cleave them. The cleaved strand is then used
to modify something else
Restriction Fragment Lenth Polymophism (RFLP): Molecular
biologists study the fragment length differences in individuals
or groups of individuals
DNA fingerprinting
Immune Systems: When bacteriophage (virus) injects
DNA into bacterial cell, the restriction enzyme breaks
foreign DNA into segments and renders it useless.