Looking at a single molecule (out of 11 that are measurable (white et al) this first molecule looks to be about 57nm (diameter intersecting two opposite CRD). The measurements were made with an adjusted nm marker from their figure, as described previously. The 100nm bar is determined by a rat SP-D dodecamer and the measurements for the mini SP-D are calculated with this measure, and are therefore relative. This means that the whole molecule is reduced by to just over half the full size SP-D the deletions of exons they called C-3 and C-4 from the collagen like sequence. Calculating curvature of the four arms of the dodecamer (arc length) hasn’t been completed yet but will increase the length somewhat.

It becomes obvious that the diagram of the domains of SP-D and mini-SP-D by White et al, are not to scale.  See below.