Cryo-EM Structure of a Possum Enterovirus

Figures

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  Figure 1. Cryo-EM reconstruction of the EV-F4 virion. (A) Representative micrograph of purified EV-F4 capsids. Scale bar, 50 nm. (B) Three-dimensional reconstruction central slice of the cryo-EM map. (C) Capsid surface electron potential map radially coloured according to the scale with red corresponding to a radius of 18 nm. The asymmetric unit was indicated by marking the five-, three-, and two-fold axes of symmetry with pentagon, a triangle, and an ellipse, respectively. (D) Resolution assessment of the cryo-EM reconstruction by Fourier shell correlation (FSC). (E) Atomic model of the protomer fitted into the cryo-EM density; (F) ‘Exploded’ view of atomic model of a protomer from the mature virion. Capsid proteins VP1, VP2, VP3 and VP4 are coloured in blue, green, red, and yellow, respectively.

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  Figure 2. Radially coloured surface representations of enteroviruses from different species: EV-A71 (3vbs), Coxsackie virus B4, VB3 (1pov), Poliovirus (1hxs), EV-D68 (6csg), EV-E1 (1bev), and EV-F4. Scale corresponds from black to blue corresponding for a radius of 11 nm and 18 nm, respectively.

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  Figure 3. The electrostatic surface representation of protomers from structures of animal EVs; the surfaces are coloured in gradient from blue to red corresponding from positive to negative charge, from 10 to −10 kcal/mol·e respectively. The approximate location of the canyon is indicated by a transparent band.

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  Figure 4. Conservation of protomer in animal EV capsids. Different views are indicated by 90-degree rotations starting with an external view perpendicular to the capsid surface. The protomer surface is coloured in a gradient from cyan to maroon according to sequence conservation from low to high, respectively.

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  Figure 5. Representation of the hydrophobic pocket on EV-F4 mature particle. (A) Surface representation coloured in a gradient with golden and cyan areas denote the most hydrophobic and hydrophilic areas, respectively. (B) Entrance into pocket factor with ribbon representation coloured from cyan to maroon according to sequence conservation animal EVs, from low to high, respectively; several residues guarding the entrance into the pocket are indicated. (C) Sequence alignment of residues guarding the hydrophobic pocket in several enteroviruses. EF-F4 is last in this list.