Analysis of WT and mutants core morphology and stability. (A) Envelope of WT and CA mutants was removed by detergent treatment and isolated cores were analysed by negative-stain electron microscopy. Electron microscopy pictures shown are representative of observations performed on 20 to 60 cores. The scale is indicated (90 nm) and is identical for all images shown. (B) Uncoating activity of WT and mutant cores. Results are normalized according to uncoating activity of WT cores. The values represent an average of at least two experiments ± the standard deviation.