RSV IN(1–278) is most efficient for producing intasomes. Intasomes with IN octamers were assembled under standard conditions at 18 °C for 48 h with IN(1–274), IN(1–278), or WT IN(1–286). Samples (500 μl each) were analyzed by SEC, and the profiles are shown. Molecular mass standards labeled from a to g indicate the elution volumes for the void volume and 670, 443, 158, 66, 44, and 17 kDa, respectively. Elution volume (ml) and absorbance at 280 nm are indicated. The void volume is 8.1 ml, corresponding to >700 kDa. AU, arbitrary units.