- A: alpha bundles
- X: alpha-helical domain in subunits of heterodimeric actin filament capping protein Capz
- H: alpha-helical domain in subunits of heterodimeric actin filament capping protein Capz
- T: alpha-helical domain in subunits of heterodimeric actin filament capping protein Capz
- F: F_actin_cap_B