P       sequence of amino acid residues

  T Q     stabilized by disulfide bonds

    S       local arrangement of the backbone

  T Q     stabilized by hydrophobic interactions

    T       3-dimensional structure of a protein

  T Q     stabilized by side chain interactions

    Q      arrangement of multiple subunits

  P S      stabilized by backbone atom bonds or interactions

    P       stabilized only by covalent bonds

    P       G – E – T – R – K is an example

    S       stabilized only by hydrogen bonds

    S       an α-helix is an example

  T Q     stabilized by ionic interactions

    S       a β-pleated sheet is an example

  S, T, Q   disrupted by denaturation

    P       not disrupted by denaturation

5-7. Answer with (H) α-helix; (P) parallel β-sheet; (N) antiparallel β-sheet; or (A) all of these.

    H      has a small dipole

    H      the secondary structure of myoglobin

    A      requires C=O – – –  H – N

  N P*   may include proline

  P N    side chains alternate above &
               below

    H      side chains of every 4^th residue interact

  P N    rarely includes proline

    N      2 strands connected by a b -bend

    N     

    P       has weak hydrogen bonds:

    H      side chains are all outside

    P       .

* Proline is found only at the end of a minority of α-helices, so I expected the answer to be either type of β-pleated sheet. However, a student wrote a note reminding me that proline can be found at the end of an α-helix, which makes A (all) appropriate, if you include absolutely all cases. Answering A = - 0.5; answering H is incorrect.