Fig. 1

Varying degrees of influence of different length indels on the structural shift of their flanking regions. The data derive from Indel Flanking Region Database. Each data point in the figure includes more than 1000 samples. The flanking region contains respective ten amino acid sites nearest to indels within each side of an indel. The degrees of structural shift of the flanking regions (expressed as RMSD) increase with the lengths of their indels (L), the shift can be well fitted by a first-order exponential decay (increasing form) model that could be represented as follows: RMSD = c1*exp.(−L/c2) + c3. In this equation, c1, c2, and c3 are empirical parameters. According to this relationship, the approximate weight values of other length indels can be calculated based on the indels with the length of one amino acid residue. The weight value represents the multiples of total structural shifts of flanking regions for indels with the length of L relative to that of the indels with the length of one amino acid residue