General question
To determine the extent to which non-local factors influence the formation of secondary structural elements
Methodology
Design the longest possible sequence that can fold into an alpha-helix when inserted into one place in a protein sequence and a beta-sheet when inserted into another. Two key references are: on a Chameleon peptide[1] and an analysis of Helix-to-Strand Transition Between Peptides with Identical Sequences[2].
Seeing is believing
To simplify the figure, the entire IgG-Binding domain[3] is colored . Now displaying, in pink, the amino acids in the region , are change to the Chameleon sequence, i.e. AWTVEKAFKTF (only 5 amino acids are mutated), specifically from/to:
TTYKLILNGKTLKGETTTEAVDAATAEKVFKQYANDNGVDGEWTYDDATKTFTVTEK
TTYKLILNGKTLKGETTTEAVDAWTVEKAFKTFANDNGVDGEWTYDDATKTFTVTEK
If a similar change from the Wild-Type to where 5 amino acids, in the region are changed to the Chameleon sequence, specifically from/to:
TTYKLILNGKTLKGETTTEAVDAATAEKVFKQYANDNGVDGEWTYDDATKTFTVTEK
TTYKLILNGKTLKGETTTEAVDAATAEKVFKQYANDNGVDGAWTVEKAFKTFTVTEK
The 3D structure of the Chameleon sequence, AWTVEKAFKTF, appears to adopt to its environment.