Protein Secondary Structure PDF
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This document discusses protein secondary structure, focusing on the arrangement of residues, the factors influencing secondary structure formation, and the protein backbone conformation. Dihedral angles and Van der Waals clashes also play important roles in protein folding.
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Protein secondary structure Secondary structure Leninger Fig 3-13 Secondary structure reflects the arrangement of residues close in sequence Most residues in most proteins can be seen to be forming either a-helices o...
Protein secondary structure Secondary structure Leninger Fig 3-13 Secondary structure reflects the arrangement of residues close in sequence Most residues in most proteins can be seen to be forming either a-helices or b-strands But what dictates that these arrangements predominate, and not others? Protein backbone conformation The conformation of the backbone can be understood by examining the bonds that join one residue to the next Three bonds join each Ca to the next Ca, so a protein’s conformation can be described by three angles per residue These angles are named omega (W), phi (F), and psi (Y) Dihedral angles –definition A D B C Given four atoms A-B-C-D connected in a row The dihedral angle is the angle made between the A-B bond and the C-D bond when looking down the B-C bond Measured in a clockwise direction Van der Waals clashes dictate single-bond dihedral angle preferences Single bonds are short (
