Fig. 6: MFAP4 octamer chains.

A 2D classification of MFAP4 particles in TBS/Ca²⁺ reveals octamer-chain classes and solitary octamer classes (box size is 723.0 Å nm). B Particles from the selected octamer-chain 2D classes were used to generate and refine a map of two closely apposed MFAP4 octamers with connecting EM-density (grey). This reference map was used for masking and subsequent multibody refinement. C Maps of the central MFAP4 octamer (pink) and partner octamer (green) produced from multi-body refinement are presented superimposed on the consensus map of both bodies and (D) alone. E The first, third, eighth, and tenth multibody refinement maps are shown along the first three principal components of movement. The first (red) and second (yellow) principal components of movement describe a swinging movement of the partner relative to the central MFAP4 from left to right or right to left, respectively. The third (blue) principle of movement describes a twisting movement of the partner relative to the central octamer. These maps are shown superimposed on the central octamer map.