Exercises

1.1

On a photocopy of Figure 1.1a, draw a 25Å wide horizontal strip that indicates the position of the membrane. (The height of the entire complex in Figure 1.1a is 132 Å.)

1.2

From an inspection of Figures 1.3 and 1.4, which pairs of subsunites of the reaction centre make contacts with each other?

1.4

Referring to Figure 1.4, how many transmembrane helices do you see in the L and M subunits?

1.5

On a photocopy of figure 1.4, number the helices in one molecule. Then number the helices in the other molecule so that helice related by symmetry have the same number.

Problems

1.1

The amino acid sequences of theL and M chains of the R. viridis reaction centre ahve the following optimal alignment:

1.2

The charged amino acids are arginine (R) and lysine (K) (positively charged) and aspartic acid (D) and glutamic acid (E) (negatively charged). Using a highlighter, indicate all stretches in the sequences of the L and M proteins (see Problem 1.1) that contain at least 8 sucessive uncharged amino acids. Ompare the number you find to the number of transmembrane helices.

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Question:

Where did John and Max do their work?

Question

Where did Robert, Johann and Hartmut do their work?