Which (phi, psi) pair of bond angles is closest to those of the residues shown in the figure below?

Silk fibroin contains predominantly β sheet conformation. Which of the following is true regarding its β sheets?

The diagram illustrates:

The major reason that antiparallel β-sheets are more stable than parallel β-sheets is that the latter:

What type of β-sheet is presented in the figure below? Draw all hydrogen bonds between appropriate groups.

Draw a two-stranded antiparallel β-sheet with appropriate hydrogen bonding between the following peptides:                                   

1) L-A-D-Y.                   

2) G-A-G-A.