terminatornukleotider

Terminatornukleotider, also known as chain-terminating nucleotides, are modified versions of normal nucleotides used in DNA sequencing and molecular biology. Unlike standard nucleotides, which have a 3'-hydroxyl group essential for DNA chain elongation, terminatornukleotider possess a modified 3' position that lacks this hydroxyl group. This structural alteration prevents the formation of a phosphodiester bond with the next incoming nucleotide, effectively halting the polymerization process.

In DNA sequencing, particularly in the Sanger sequencing method, terminatornukleotider are labeled with different fluorescent dyes, each corresponding to a specific base (adenine, guanine, cytosine, or thymine). When DNA polymerase incorporates a terminatornukleotid into a growing DNA strand, the synthesis of that particular strand stops. By using a mixture of all four labeled terminatornukleotider, a collection of DNA fragments of varying lengths is generated, each ending with a known base indicated by its fluorescent tag. These fragments are then separated by size, and the sequence is read by detecting the order of the fluorescent signals.

Terminatornukleotider have been instrumental in the advancement of genomics, enabling the rapid and accurate determination of DNA sequences. Their use has paved the way for large-scale sequencing projects, including the Human Genome Project, and continues to be a cornerstone technique in molecular research and diagnostics.