Structural analysis of herpes simplex virus by optical super-resolution imaging

Laine, Romain F.; Albecka, Anna; van de Linde, Sebastian; Rees, Eric J.; Crump, Colin M.; Kaminski, Clemens F.

Here we developed a method to estimate the average distance between the centre of the capsid and the centre of the outer protein layer (tegument or envelope), as detailed in Supplementary Note 6. Briefly, the displacement between the centre of the considered layer (tegument or envelope, determined by a fitted circle) and the centre of the capsid (determined by localization of the centroid of the mTurquoise-VP26 fluorescence) was calculated for a large number of particles and the data were analysed with a further model-based analysis. This approach is related in nature to that of a recent investigation of sub-virion protein distribution in the related herpesvirus pseudorabies virus 46 . In the latter work, the displacement between the centroids of the wide-field fluorescence patterns from dually labelled virions was determined with high precision. The results of our analysis are shown in Supplementary Fig. 5b . After correction for the residual chromatic random error, the offset was estimated as 12, 7 and 24 nm for gD, VP16 and pUL37, respectively. The order of magnitude of this offset is in good agreement with the value determined by ET 4 , although greater than expected for pUL37.