A common sequence-associated physicochemical feature for proteins of beta-trefoil family.

Different amino acid sequences can fold into similar tertiary structures but the reasons for it are not very clear. It has been suggested in the literature that these sequences may have some common features associated with them but the exact nature of such shared properties remains largely unknown. We studied a representative sample of proteins from the beta-trefoil family and observed that their amino acid sequences, despite being considerably divergent from each other, can be accounted for by matching to a repetition of three physicochemically similar segments. This observation in turn is consistent with the three-fold pseudo-symmetry in tertiary structures of these proteins.