Physical Molecular Biology Section
Quantitative Measurements by AFM
Every point on a digital AFM image
has an X, Y, and Z coordinate. In our measurements, centers of consecutive
nucleosomes in a fiber are marked by consecutive computer mouse clicks
which record both X, Y position and height (Z) of the top of the nucleosomal
image. Hence it is very easy to make a large quantity of measurements
very quickly of nucleosome center-to-center distances, angles formed by
the intersection of lines connecting the centers of three successive nucleosomes,
and the heights of nucleosomes in the fiber. From these kinds of
measurements, we have constructed histograms which often can have more
than 2000 points per histogram; this establishes the strength of SFM as
a quantitative tool.
Yang, G., Leuba, S. H., Bustamante, C., Zlatanova, J. and van Holde, K.
Role of linker histones in extended chromatin fibre structure. Nat Struct Biol. 1(11) 761-763 1994