Alanine scanning

In molecular biology, alanine scanning is a site-directed mutagenesis technique used to determine the contribution of a specific residue to the stability or function of a given protein.

[1] Alanine is used because of its non-bulky, chemically inert, methyl functional group that nevertheless mimics the secondary structure preferences that many of the other amino acids possess.

[6] Alanine scanning was used to determine simultaneously the functional contributions of 19 side chains buried at the interface between human growth hormone and the extracellular domain of its receptor.

Another critical application of alanine scanning is to determine the influence of individual residues on structure and activity in the prototypic cyclotide kalata B1.

In this study, several Cry4Aa mutants were made by replacing the residues of potential receptor binding site, loops 1, 2, and 3 in domain II with alanine.

Example of alanine scanning. The native protein (top row) and each possible point mutation to alanine is considered.