I am searching for the orientation of SP-A within the structure of tubular myelin, not for that purpose really but actually to figure out whether it is SP-A or SP-D that accumulates as a highly organized protein in the cisternae of the RER in type Ii cells of the peripheral lung.  Four composites from readily available images of tubular myelin found online show an angular arrangement of the 6 trimers in the octadecamer proposed to be surfactant protein A.

Actually these four particular images come from a paper by Mary Williams, and the micrograph was saved as a screen print, pixels inflated, pasted into photoshop, and 4 individual lattice structures were cut and skewed to fit more-or-less together, their grey and dark and white portions aligned as in a “square” tubular myelin lattice- without changing any of the actual structural data.  With the select tool, white and light grey was removed from each layer and transparency adjusted. Using corelDRAW the transparent images were centered,  and exported in register, along with an approximate diagram of the positions of the carbohydrate recognition domains (6 surfactant protein A groups (18 CDRs total – so 3 were lumped into one circular object) superimposed.  Diagram is seen as a dotted lines at the beginning of the video, and solid circles at the end of the video (no neck or carbohydrate portions of surfactant protein A were drawn in this case diagram). Video was created in Swishmax 4.