Fig. 4.
Distributions of cc-distances in 172-α7 and 208-6 nucleosome arrays, measured by AFM after adsorption under low salt conditions. acc-distances in 172-α7 arrays measured in three samples with a combined average number of NCPs per array nncp-av = 4.2. bcc-distances for exclusively 172-α7 nucleosome arrays with number of NCPs nncp <5, corresponding to nncp-av =3.2. ccc-distances measured in 208-6 nucleosome arrays (nncp-av =3.2). Numbers and arrow heads indicate cc-distances expected for a uniform nucleosomal phasing with the monomer lengths of 172 bp (a, b) and 208 bp (c), as calculated assuming Eq. (2). a is the number of unoccupied repeats between successive nucleosomes. The distance distribution begins at a value of 11 nm, the diameter of the NCP, meaning that a few measured distance values smaller than 11 nm were added to the first bin. The bin width of 12 nm corresponds to the length difference between monomer lengths of 172 and 208 bp (36 bp). Error bars indicate the square root of the number of observations in each bin