Structural plasticity associated with the β-propeller architecture

Abstract

The β-propeller architecture observed in protein tertiary structure and classified into the five different types according to number of ‘blades’ (or β-sheets) and a sixth type classified according to the secondary structure composition of the blades (the ββαβ-molecular unit) is characterized by variations (or plasticity) in the structure. These correspond to the number of β-strands associated with the blade, the number of amino acid residues associated with equivalent β-strands in the different blades and the presence of α-helices and twisted β-strands. We have generated a β-sheet associated β-strand pattern that may be important for protein structure prediction and modeling. Analysis of the β-propellers extracted primarily from the SCOP database revealed there are 179 β-propellers. The examination of the secondary structure corresponding to the β-propeller using PDBsum that was useful to define the β-sheet associated β-strand pattern, combined with visualization on graphics display revealed structural plasticity associated with the β-propeller architecture. Particularly, the type 6- and 7-bladed β-propellers known to be associated with sequence and functional diversity are more common and associated with relatively more structural variations compared to the other β-propeller types.