Just looking at some grayscale peaks in a plot of a surfactant protein D dodecamer and noticed that one hexamer, plotted in ImageJ, of this molecule (AFM, 41 aka 45 – sorry for that id i have given this dodecamer) with a CorelDRAWx5 photopaint program and a 50 percent-10px minimum filter shows a drag on the peaks which I dont think i have noticed before. These occur on one trimer (left side, minimally on the first peak with the red arrow, then on the next four peaks more prominently) of the hexamer plotted (see actual dodecamer – bottom image) of this dodecamer, but not on the second trimer (right side of the plot).

It looks like a “nice” demonstration of a drag artifact.  A displacement from left to right seen on the LEFT half of this plot (horizontal trimer), but not the right side of the plot (vertical trimer).

Original image used to make this plot is below. It is interesting that the drag did not appear on the trimer which is more vertically oriented, i.e. the right hand trimer (closer inspection of the image also shows a smearing of that trimer which till now I had not paid any attention too, but it certainly translated into a change in the plot). bar=100nm