Question

Consider two molecules of a tetrapeptide composed of only alanine residues. Draw the hydrogen bonding interactions that result when these two peptides adopt a parallel β-pleated sheet arrangement. Answer this same question for the antiparallel β-pleated sheet arrangement.

Short answer

In a parallel$\mathit{\beta }$-pleated sheet, the strands run in the same direction from the N- to C-terminal amino acid. The given tetrapeptide is composed of alanine.

The dotted lines represent the intermolecular hydrogen bonding.

Step-by-step solution

Parallel β -pleated sheet

In a parallel$\mathit{\beta }$-pleated sheet, the strands run in the same direction from the N- to C-terminal amino acid. The given tetrapeptide is composed of alanine.

The dotted lines represent the intermolecular hydrogen bonding.

Antiparallel β-pleated sheet

In an antiparallel $\mathit{\beta }$-pleated sheet, the strands run opposite.

The dotted lines represent the intermolecular hydrogen bonding.