journal menu
![[Figure 8]](yt5034fig8mag.jpg)
|
|
Figure 8
1-D helical symmetry determination for a complicated helical structure. This example illustrates that the guideline defined for 1-D helical symmetry determination is capable of giving a unique symmetry assignment [n1, n2, φ, δ] to an intricate helical structure. The asymmetric subunit of the bacterial flagellar hook (Fujii et al., 2009  ; PDB entry 3a69; EMD-1647) contains three protein domains spanning the inner, middle and outer layers of the helical structure. Based on individual domains, the best protofilament in each domain forms a set of six-start, five-start and 11-start helices, respectively, from the outer to the inner layer of the helical structure. The pictorial helical descriptions for three different symmetry assignments are given under [6, −1], [5, −1] and [11, −6] symmetry. The guideline prefers the [11, −6] symmetry assignment simply because the 11-start helix has a twist angle closest to zero and the six-start helix is the protofilament with the largest number of contacts between the asymmetric units along the protofilament. |
![[Figure 8]](yt5034fig8.jpg)
 | STRUCTURAL BIOLOGY |
ISSN: 2059-7983
access
