Detection of Residual Helicity in ACTR with Millisecond Hydrogen Exchange

3 Detection of Residual Helicity in ACTR with Millisecond Hydrogen Exchange 

It would be possible to deliberately assemble a subset of ACTR peptides that better display this residual helicity (i.e., cherry picking). Conversely, a subset of peptides could be chosen that shows that there is no residual helicity in ACTR. To avoid these potential problems, we used a residue-by-residue averaging of values of all peptides that cover a given residue. The approach has been described in greater detail elsewhere [53]. For a set of i peptides, a given residue, R., will contribute to measurable exchange (E. = 1) when it is not in the first two positions of the peptide i and is not a prohne  

Although this approach provides data on a residue-by-residue basis, it is not truly residue resolved. Averaging of peptide segments leads to blurring of the data. Nevertheless, simulations demonstrate that this approach can reliably map the boundaries between helical and unstructured elements [53]. 

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