FIG 4.

E protein of dengue virus and its subdominant domain III. (A) Schematic of dengue virus and its surface E protein. The mature dengue virion (left) is covered by 30 rafts, each of which contains three antiparallel E protein dimers. One raft is framed in black, and a single dimer is shown as ribbons (right). The positions of the three domains (DI to DIII) are indicated for one E protein monomer. While domain III is subdominant, the fusion loop in domain II is part of an immunodominant site. Adapted from reference 113. (B) Protein maturation during dengue virus replication (114). In the endoplasmic reticulum (ER), the surface of the immature virus particle is covered by trimeric prM-E spikes, in which prM prevents premature membrane fusion promoted by the fusion loop (red spot) in the E protein. During transport through the acidic trans-Golgi network (TGN), the complex is rearranged and prM is then cleaved into pr and M. The small M fragment is retained in the viral membrane, with negligible surface exposure, while the pr fragment remains bound to the FL. When the virus particle is released from the cell, pr dissociates from the complex and the FL becomes largely hidden within the E dimer (113–115). Adapted from reference 114 with permission of AAAS.