Endonucleases break nucleic acid bonds within a strand, while exonucleases only cut at the end. Restriction endonucleases attack specific sites and are used in genetic engineering. Bacteria use endonucleases to defend against viruses, and methylation protects their own DNA. Researchers use endonucleases to insert new genetic material, and labs sell them to other labs. Working with endonucleases requires skill and caution.
An endonuclease is a specialized enzyme that can break the bonds between nucleic acids in a polynucleotide chain, producing two fragments. These enzymes can act in both DNA and RNA to cut from within a strand. Some endonucleases, known as restriction endonucleases, attack specific sites within strands of RNA and DNA, recognizing particular sequences. These enzymes are very valuable in scientific research when people want the ability to change genetic information, such as in genetic engineering.
In contrast, an exonuclease can only cut away the genetic material at the end of a DNA or RNA strand. Endonucleases are used by bacteria and archaea as part of their defense mechanisms. Some of the earliest observations of these enzymes in action come from bacterial research, and bacteria are used to produce endonucleases on a large scale for research purposes.
Within a bacterium, an endonuclease is designed to fend off viral attacks by cutting foreign DNA so that it becomes non-functional. The body protects its DNA from the actions of the endonuclease through a process known as methylation. Methylation prevents the endonuclease from acting, ensuring that the organism’s DNA is left intact. Foreign DNA, however, is not so lucky and the endonuclease will precisely cut through the DNA backbone in two places, cutting it to create separate strands. Depending on which endonuclease is involved, the events can be “smooth” or “sticky,” referring to where in the strand the DNA or RNA is severed.
Researchers can use known restriction endonucleases to cut DNA in desired target areas, creating a convenient insertion site. At this point, new genetic material can be inserted, with the aim of coaxing the expression of an entirely new gene. This can be used to do things like introduce herbicide resistance into crops so farmers can spray fields to keep weeds at bay.
Laboratories that produce endonucleases sell their products to researchers and other laboratories. The lab describes the ways in which a product can act, allowing researchers to determine which product would be best suited for its intended uses. Working with endonucleases can be complicated and requires patience and skill. One might think of an enzyme like a restriction endonuclease as a very small, very fussy set of scissors that can be used to make a project, but it can also malfunction if not handled properly, cutting in the wrong place or not cutting at all. .
Protect your devices with Threat Protection by NordVPN
