(
A) Coomassie-stained SDS-PAGE analysis of purified pUL7:pUL51(8–142) following 30 min incubation at room temperature with varying molar excesses of the cross-linking agents DSSO (left) or DSBU (right). Theoretical migration of proteins corresponding to pUL7, pUL51(8–142), and 1:1, 1:2, 2:2 or 2:4 complexes thereof, are indicated. (
B) Cross-linking restraints used for pseudo-atomic modelling of the pUL7:pUL51(8–142) heterotrimer. Restraints used for all models (‘constant cross-links’) and permuted restraints (‘variable cross-links’) that were used for the five best-fit (lowest χ
2) models are shown. (
C) The five best pseudo-atomic models (lowest χ
2) generated by fitting to the pUL7:pUL51(8–142) SAXS profile as described in
Materials and Methods using the restraints shown in (
B). The core heterodimer of pUL7 (residues 11–234 and 253–296; green) and pUL51 (residues 41–89 and 96–125; #1, cyan) and the additional molecule of pUL51 (residues 41–89 and 96–125; #2, yellow) are shown as ribbons (right). Additional regions modelled using I-TASSER or CORAL are shown as spheres. The fit of the computed scattering (yellow) to the pUL7:pUL51(8–142) SAXS profile (aqua) is shown for each model (left), as are reduced χ
2 and CorMap
P-values (
Franke et al., 2015;
Petoukhov et al., 2012).