Renaturation three-dimensional structure

This classic experiment, carried out by Christian Anfinsen in the 1950s, provided the first evidence that the amino acid sequence of a polypeptide chain contains all the information required to fold the chain into its native, three-dimensional structure. Later, similar results were obtained using chemically synthesized, catalyti-cally active ribonuclease. This eliminated the possibility that some minor contaminant in Anfinsen s purified ribonuclease preparation might have contributed to the renaturation of the enzyme, thus dispelling any remaining doubt that this enzyme folds spontaneously. 

Renaturation. The process of returning a denatured structure to its original native structure, as when two single strands of DNA are reunited to form a regular duplex, or the process by which an unfolded polypeptide chain is returned to its normal folded three-dimensional structure. 

Chemists have long appreciated that a protein s primary amino acid sequence determines its three-dimensional structure. It has also been known for some time that proteins are able to carry out their diversified functions only when they have folded up into compact three-dimensional structures. The protein-folding problem first gained prominence in the 1950s and 1960s, when Christian Anfinsen demonstrated that ribonuclease could be denatured (unfolded) and renatured reversibly. 

We know that the sequence of amino acids ultimately determines the three-dimensional structure of a protein. We also know that proteins can spontaneously adopt their native conformations, be denatured, and be renatured back into their native conformations, as was shown in Figure 4.20. These facts can lead us to the following question ... 

Antigen antibody recognition is dependent on protein structure. A conformational change in a protein caused by formalin fixation may mask the epitope and thus affect the antigenicity of proteins in formalin-treated tissue (Montero 2003). The antigen retrieval leads to a renaturation or at least partial restoration of the protein structure, with re-establishment of the three-dimensional protein structure to something approaching its native condition (Shi et al. 1991). 

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