Figure 12.

The topological analysis of the beta sheet structure extracted from beta barrel 2GR8. The coarse-grained representation is employed with C_α atoms in the green color in a. There are 128 atoms organized in 12 beta sheets. The topological fingerprint of the beta sheet structure is depicted in b. The red boxes are zoomed in and demonstrated in c and d. There are 128 β₀bars and 98 β₁ bars. It is seen from b and c that in the β₀ panel, 12 out of 128 bars persist beyond 3.8Å, which corresponds to 12 isolated beta sheets. The longest β₁ bar in b is due to the large hole in beta barrel structure. Other β₁ bars are formed from every adjacent 4 C_α atoms as discussed in the earlier analysis of parallel beta sheet structure. Due to the mismatch, adjacent two sheets contribute around 8 β₁ bars, which accounts for 12 × 8 = 96 short-lived β₁ bars. Together with the bar for the global intrinsic ring, it is estimated that there are 97 β₁ bars. Although computational result shows 98 β₁ bars, one of them (the fifth from top) is barely visible.