Cooperative Transition between Open and Closed Conformations in Potassium Channels
Figure 5
The dynamic coupling between residue pairs in the KcsA homotetramer.
The axes mark the residue numbers in each subunit. The magnitude of the positive and negative correlations between the dynamic fluctuations of the amino acids (average of the seven slowest modes) is color-coded using the red-through-blue scale on the right. (A) Interactions within subunit A; (B) interactions between residues in subunit A and residues in its nearest neighbor (subunit B; the right neighbor in the homotetrameric structure from the intracellular view of Figure 1E); (C) interactions between residues in subunit A and its juxtaposed neighbor (subunit C) in the tetramer. The structural elements (I to IV) and the helices are marked on the axes using the convention of Figure 3, and the approximate location of the selectivity filter is marked with “S”. The calculations were based on the average of the seven slowest modes of motion.