ligáció

Ligación, or ligation, is the act of joining two structures by a ligature or chemical bond. In scientific and medical usage, the term describes processes that bind or connect biological molecules or tissues. The concept is central in molecular biology and in surgical practice, among other fields.

In molecular biology, ligación refers to the enzymatic joining of two DNA fragments by a DNA ligase. The reaction forms a phosphodiester bond between a 5' phosphate and a 3' hydroxyl. Ligation is essential for DNA replication and repair and is routinely exploited in cloning and recombinant DNA techniques to insert fragments into vectors. DNA ends can be cohesive (sticky) or blunt; cohesive ends promote more efficient ligation. Ligation conditions depend on the enzyme, temperature, and the DNA ends, with common enzymes including T4 DNA ligase. In modern cloning, ligation is often preceded by restriction digestion, gel purification, and, in some cases, alternative methods that bypass ligation.

In medicine, ligación commonly refers to ligation of blood vessels or ducts during surgery, often by tying them with a suture (ligation) or by using clips or bands. This technique aims to halt bleeding, prevent leakage, or isolate a structure. The procedure requires precision to avoid tissue injury and is chosen based on vessel size and tissue type.

Other uses include ligation in bioconjugation or chemical ligation, where two molecules are joined without enzymatic catalysts. The term remains broad, with context providing specific meaning.