Hybrid modeling of large targets
When modeling a large protein complex templates might be available just
for some parts of it. During CASP14 this was the case for heteromeric
targets H1060 and H1097. For both of these targets more accurate models
were generated for those parts that had templates.
H1060 was a viral protein complex containing 27 subunits (5 homomeric
rings bound to each other, A6B3C12D6, Fig. 4). We found templates for
all the rings, and generated models of medium accuracy for all of them
using either comparative modeling or template-based docking methods.
Next, we tried to do template-based docking of the ring models to each
other using another viral template, but for such a large complex the
docking was complicated. As a result, the accuracy of hetero-complex
(H1060v1) model is lower.
Similar situation was observed with hetero-pentamer H1097, where we
tried to dock the domains of the 5th subunit to a
homology model of a hetero-tetramer albeit with limited success
(Supplementary Table S2).