Looking at the RCSB structure diagrams for SP-D and a mutant SP-D described by Goh, et al, released 2013, boy I can not see the difference in the structures. The SP-D top three views (human SP-D) look identical (i rotated it ever so slightly to make sure all the residues cold be seen) to that modeled for two mutations, (ref and mutation sites noted in the image).  Please do tell why this SP-D which doesn’t appear to be any different than the views above would bind influenza A virus so much better than the wt neck and carbohydrate recognition domain.  The NCRD protein is viewed from the top… presumably where the trimeric structure should connect with the carbohydrates on the virus?