Preferred indel sites in different SCOP classes.

The PB bounds (di-PBs) that act as sites for insertions/deletions of different lengths are listed. To obtain a better picture of the local fold, the two PBs that are seen on both sides of the indel site were also analysed. The most frequent series are listed and their occurrence frequencies are given in parentheses. PROMOTIF [42] was used for assignment of the local fold corresponding to these frequent PB series. Those regions assigned as coils and are usually found as capping motifs, are labelled as ‘caps’. The following are the local fold definitions implied by the PROMOTIF assignment abbreviations: (see also Table 1). HPX:Y – β-hairpins, X and Y indicate the number of residues in loop, based on two different rules [42], GTCLA – Classic γ-turns (φ = 75.0±40,ψ = −64.0±40).