Daily Archives: May 6, 2022

Peak counts of a single surfactant protein D molecule (an AFM image): Possible peak in the center of the N term peak?

Only 18,  times out of 636 plots of surfactant protein D trimers was there something that could be identified as a peak at the top center (or close to center) of the N termini junction peak (light green in the two top plots below).  This was found in 3 ipeak.m signal processing settings, and one Lag-Threshold-Influence algorithms used in a batchprocess (also signal processing), and the rest of the time with counts of plots that had been image processed.  One of the more prominent displays of that peak came from Gwyddion, gaussian blur and limitrange 100-255 filtering.

The bottom plot below (Gwyddion, gaussian blur and limitrange filters) was one of the two plots given to the citizen scientists from which to count peaks.  None of those individuals chose to identify this thin N termini blip as an actuall PEAK.  It clearly exists sometimes, but its relevance is not known.

The division of the N termini peak into TWO clearly identified peaks (rather than three which would include the central “green” peak below) was more common.