sisselõikuskoha

A sisselõikuskoha, often translated as a "cut site" or "restriction site," is a specific DNA sequence that is recognized and cleaved by a restriction enzyme. Restriction enzymes are a class of enzymes produced by bacteria as a defense mechanism against invading viruses. They act like molecular scissors, cutting foreign DNA at precise locations.

Each type of restriction enzyme recognizes a unique, often palindromic, DNA sequence. For example, the enzyme EcoRI recognizes the sequence GAATTC and cuts between the G and A on both strands, leaving "sticky ends" with short single-stranded overhangs. Other enzymes, like HaeIII, recognize the sequence GGCC and create blunt ends, with no overhangs.

The specificity of sisselõikuskohad is crucial for molecular biology techniques. In recombinant DNA technology, restriction enzymes are used to cut both the DNA of interest and a vector, such as a plasmid, at compatible sites. This allows the DNA fragment to be inserted into the vector, forming recombinant DNA. This process is fundamental for gene cloning, genetic engineering, and DNA sequencing.

The study and identification of sisselõikuskohad have led to the development of numerous tools and techniques used in laboratories worldwide, revolutionizing our understanding and manipulation of genetic material.