Site de restriction
- Site de restriction
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Sites de restriction
Les sites de restriction sont des séquences particulières de nucléotides qui sont reconnues par les enzymes de restriction comme des sites de coupures dans la molécule d'ADN. Les sites sont généralement palindromiques, et une enzyme de restriction spécifique pourra couper entre deux nucléotides dans le site en question (enzyme de type II) ou en un autre endroit de la molécule (type I et type III).
Par exemple, l'enzyme de restriction EcoRI reconnait la séquence GAATTC et coupe entre le G et le A sur le brin du dessus et celui du dessous, laissant ainsi à la fin une extrémité AATT. Ces extrémités peuvent être utilisées pour lier cette pièce à un autre brin d'ADN complémentaire grâce à l'ADN ligase.
Utilisation
En médecine, la mutation ponctuelle de substitution intervenant dans le cas de la thrombophilie par mutation du facteur V de Leiden modifie le site de restriction de l'enzyme MnlI. On peut utiliser cette particularité pour le dépistage de la mutation. nbb
Voir aussi
Portail de la biologie cellulaire et moléculaire
Catégorie : Enzyme de restriction
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Restriction enzyme — An enzyme from bacteria that can recognize specific base sequences in DNA and cut the DNA at that site (the restriction site). A restriction enzyme acts as a biochemical scissors. Also called a restriction endonuclease. A restriction enzyme is a… … Medical dictionary
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Site-directed mutagenesis — Site directed mutagenesis, also called site specific mutagenesis or oligonucleotide directed mutagenesis, is a molecular biology technique in which a mutation is created at a defined site in a DNA molecule. In general, this form of mutagenesis… … Wikipedia
Restriction site — Restriction sites, or restriction recognition sites, are specific sequences of nucleotides that are recognized by restriction enzymes. The sites are generally palindromic, (because restriction enzymes usually bind as homodimers) and a particular… … Wikipedia
restriction endonucleases — (= restriction enzymes) Class of bacterial enzymes that cut DNA at specific sites. In bacteria their function is to destroy foreign DNA, such as that of bacteriophages (host DNA is specifically modified at these sites). Type I restriction… … Dictionary of molecular biology
restriction site — restriction site. См. сайт рестрикции. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) … Молекулярная биология и генетика. Толковый словарь.
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Restriction fragment length polymorphism — A Restriction fragment length polymorphism (or RFLP, often pronounced as rif lip ) is a variation in the DNA sequence of a genome that can be detected by breaking the DNA into pieces with restriction enzymes and analyzing the size of the… … Wikipedia
