The pattern of frequently occurring supersecondary motifs in proteins

Supersecondary motifs have been analysed in 240 proteins defined at resolutionsof 0.25 nm or better. The supersecondary motifs have been classified into four types:αα,αβ,βαand ββ, and cluster analyses carried out based on the 3D structures of supersecondarymotifs to assess the optimal basis of classification. Using five classes of residueconformation—a, b, e, l, t—in the non-regular structure regions, we have identified 50classes of supersecondary motifs that occur more than 5 times, and 11 classes that occurmore than 25 times. The sequence and pattern of solvent accessibility of the 11 more fre-quently occurring supersecondary structures have been characterized. The results have