Comparison of the dynamics [residue-wise root mean square fluctuation
(RMSF)] of P450eryF for the crystal structure (red) and MD simulations
of the wild-type protein (black) and the R185M mutant (blue). The green
lines on the x axis indicate residues A74, L76, I174,
V176, and R185. The locations of the peaks in RMSF of the residues in
the channel region are similar in all three curves. The four hydrogen
bonds to R185 locally reduce the RMSFs in all three curves but the
effect is clearly the smallest for the R185M mutant. After partial
breaking or rearrangement of these H-bonds, considerable conformational
freedom is expected in the B/B′ and F/G loop regions, thus allowing
channel opening. In the R185M simulation the N-terminal residues also
show greater flexibility, which is required for channel opening.