Fig. 1: DENV3-CH53489 particles induced by temperature to form clubSPs.

a Micrographs of DENV3-CH53489 incubated at various temperatures. A large proportion of the particles transform from spherical to clubSPs (a representative is boxed in red) at 29 and 37 °C. Micrographs represent one of eight independent experiments. b Graph showing percentage of clubSPs increase gradually with temperature. The maximum percentage of clubSP is reached at 37 °C. Data are presented as mean values with error bars represent standard deviations (±SD) calculated from three individual experiments. Source data are provided in the source data file. c Representative micrographs of anti-DIII E protein Fab 8A1 added to DENV3-CH53489 before (i) or after (ii) virus is exposed to 37 °C. In (i), Fab 8A1 inhibits clubSP formation, whereas (i) there are similar amounts of clubSP, as the uncomplexed control in (a). (Right) The Fab binds to the head (open arrow) and also the tip of the tail (closed arrow) of DENV3 clubSPs. n = 3. d When Fab C10 is added to DENV3-CH53489 (i) and ZIKV (ii) prior to exposure to 37 °C, the surface becomes spiky, indicating Fab binding. Upper right corner on each micrograph shows 2D average (top panel) of the projections, which are boxed sequentially along the filaments with partially overlapping regions, and also their power-spectrum (bottom panel) of the central sections of the tail portion of clubSP or the body of catSP. Fab density is indicated by an arrow in the 2D averages. A representative clubSP or catSP is boxed in red in the micrographs. Micrographs represent data from two independent experiments for both DENV3-CH53489 and ZIKV. e Micrograph showing the DENV3-CH53489 clubSPs (red box) are mostly mature virus, as anti-prM Fab DV62.5 binding was not detected in the 2D averages (bottom panels) of either the head or tail of the clubSP particle. Fab DV62.5 was observed to bind to the spherical spiky immature virus population (black box) as shown in Supplementary Fig. 4b. Uncomplexed smooth-surfaced mature spherical virus is boxed in blue. Scale bars in micrographs represent 100 nm. Micrographs are from one experiment. f CryoEM map of asymmetric reconstruction of the DENV3-CH53489 clubSPs shown in different views.