Fig. 5: Interactions in L-BC capsid are mediated by domain swapping between A but not B subunits.
From: Structures of L-BC virus and its open particle provide insight into Totivirus capsid assembly
a Cartoon representation of L-BC icosahedral asymmetric unit and A subunit from a neighboring icosahedral asymmetric unit related by fivefold rotation. The subunits are viewed from the inside of the particle. Subunits are distinguished by color: A in blue and B in red. The C-terminus of the A subunit, colored and highlighted in magenta, participates in domain swapping between adjacent A subunits. Domain swaps propagate around the fivefold symmetry axis counterclockwise (magenta arrows). The C-terminus of the B subunit, colored and highlighted in green, remains within the bulk of the protein. b Detail of area outlined by dashed square in a. The domain swap between A subunits is stabilized by salt bridges at two positions denoted I and II and indicated with black ovals. Side chains of residues forming the salt bridges are shown in stick representation. The corresponding residues from the C-terminus of the B subunit are highlighted with dashed ovals and Roman numerals, however, they do not form salt bridges.
