Annealing

Annealing

Annealing is a process leading to the formation of a folded nucleic acid structure by first heating the solution containing the nucleic acid strands to a temperature high enough to melt whatever partially folded structures may exist, and slowly cooling that solution to allow the strands to assemble into the desired, fully folded structure. The fully folded structure may be a duplex, triplex, quadruplex or higher structure, such as a DNA origami nanostructure, but it may also be just a folded structure of a single strand, such as a ribozyme. This process is often the first step of an assay requiring functional assemblies of DNA or RNA strands. Leaving it out can give an incorrect result, as partially folded or unfolded structures do not have the same activity/function as fully folded ones. The heating ensures that the activation barrier for forming the fully folded structure is overcome. Slow cooling makes it easier for the molecules to reach the folded state of maximum base pairing and low energy. Annealing may be achieved by placing a vial in hot water and removing it again, or by more elaborate and controlled temperature programs, e.g. in a thermocycler. The term annealing is also used in other fields of research and development, for processes using other compounds than DNA or RNA.

Reference

Molecular biology techniques can be found in:

M. R. Green, J. Sambrook, Molecular Cloning: A Laboratory Manual (Fourth Edition), CSH Press, Cold Spring Harbor Laboratory Press, 2012.

http://www.molecularcloning.com/