Coiling of β-pleated sheets

Abstract

To form strongly twisted β-sheets, strands have to be coiled as well as twisted (Nishikawa & Scherga, 1976). I show that strands coil in the appropriate right-handed direction if their main-chain torsion angles fulfil the following conditions: ψ i ≅ − φ i + 1 , ψ i + 1 > − φ i + 2 , ψ i + 2 ≅ − φ i + 3 , ψ i + 3 > − φ i + 4 … Lactate dehydrogenase, pancreatic trypsin inhibitor, thermolysin and concanavalin A contain strongly twisted β-sheets and in each case the strands are coiled by their φ, ψ values fulfilling these conditions.