Extended Data Fig. 1: Estimation of sample purity from cross-linked and non-cross-linked HCMV particles.
From: Spatially resolved protein map of intact human cytomegalovirus virions
(a) Exemplary micrographs of negatively stained HCMV particles. Purification using glycerol tartrate gradients and cross-linking treatment as indicated. Scale bar represents 1000 nm. Manually selected particles are indicated by yellow circles. Representative micrographs of at least 10 per condition. (b, c) Distribution of diameters of manually picked particles of the non-cross-linked (b) or cross-linked (c) samples. Purification led to a more homogenous population of particle diameters. As previously noted25, we also find that the purification leads to membrane blebs, thus representing non-native particle morphologies. (d, e) Two cut-offs were defined to categorize unusually small (<160 nm) and large particles (>220 nm). These correspond to the median of diameters from the purified sample ± two times the standard deviation. The fraction of particles with diameters that fall below 160 nm, exceed 220 nm or fall in between are indicated for the non-cross-linked (d) or cross-linked (e) sample types. Purification results in more homogeneous particle diameters, enriching virions in the expected size range. Thus, our protocol captures the native configuration of the particles at relatively high sample purity. At least 367 particles were counted per condition.
