Fig 10.

Low pH dissociates vaccinia A26 and A26-A27 protein complexes from MVs. (A). Purified vaccinia virus MV particles (24 μg) were treated with PBS at pH 7.4 or PBS at pH 4.7 at 37°C for 3 min with or without neutralization with 15 mM Tris-HCl (pH 8), followed by centrifugation. The supernatant (Sup't) and pellet fractions were collected, separated on SDS-PAGE gels under reducing (with 2-mercaptoethanol [+2ME]) conditions, and analyzed by immunoblotting (IB) using anti-A26 (1:1,000), anti-A27 (1:5,000), anti-G9 (1:5,000), anti-A16 (1:1,000), and anti-H3 (1:1,000) antibodies. (B and C) The samples described in panel A were separated under nonreducing (−2ME) conditions on 4 to 12% SDS-PAGE gels and analyzed by immunoblotting with anti-A26 (1:1,000) (B) and anti-A27 (1:5,000) (C) antibodies. The m, d, t, and tr suffixes with the A26 and A27 proteins represent monomer, dimer, trimer, and truncated, respectively.