Figure 5.

Inter-subunit disulphide bond. (A) Cartoon diagram of two disulphide-bonded polyhedrin related by a two-fold rotation forming an extended dimer. Structures are coloured by chains and the helices are shown in cylinders. Residues involved in intermolecular salt bridges are drawn as sticks and disulphides are shown as yellow spheres in two orthogonal views. (B) SDS–PAGE of AcMNPV polyhedra under reducing and non-reducing conditions when dissolved in bicarbonate buffer, pH 10.5. Polyhedra were incubated at 80°C for 2 h to inactivate the protease associated with polyhedra before exposure to alkaline buffer. Samples were electrophoresed on 4–8% gradient SDS gels with 1 min (lanes 2–4 and 6) and 5 min (lanes 1 and 5) heating at 100°C.