Fig. 3.

Pairwise amino acid covariance. (A) Pairwise covariance between randomized positions. Connectors are labeled with the overall covariance significance between the two positions. (B) Pairwise covariance periodicity. The sum of significance scores for all amino acid pairs separated by a certain distance across the whole random region (gray circles) is compared to the average linkage in random sequences (black squares) and the maximum possible values (black line). (C) Average amino acid helical propensities at each position. The three positions with the least favorable amino acid distributions are shaded black. The line represents the average propensity of the initial pool distribution.