FIGURE 4.

PCA of secondary structural elements in the Eg5 motor domain reveals distinct conformer populations, resulting from L5-initiated effects. The score, or spatial positioning, of the data points is based on changes in percentage area of the secondary structure profiles determined by IR band narrowing. A, PCA clusters the majority of Glu-118 (■) and WT (●) data points together based on secondary structure. The Glu-116 (□) polymorphisms fall into a separate line of degeneracy with a larger disordered component. The 1642 and 1646 cm⁻¹ vectors separate these two populations. B, PCA of C-terminal L5 substitutions, Ala-133 (▴) and Asp-130 (▵), falls predominantly into the same population occupied by the N-terminal Glu-118 mutations and can be differentiated by the 1633 and 1628 cm⁻¹ vectors, respectively. C, a composite of both N- and C-terminal polymorphisms are plotted. Highlighted are the monastrol (blue) and STC (pink) data points.