ΔN6-N and ΔN6-I dimer conformations.

<p>Representative dimer conformations with number of intermolecular contacts equal to the mode (mode dimers) and tail (strongly-matched dimers) of the density histograms. Mode dimers of ΔN6-N (A) and ΔN6-I (B) at pH 7.2, ΔN6-N (C) and ΔN6-I (D) at pH 6.2. Strongly-matched dimers of ΔN6-N (E) and ΔN6-I (F) at pH 7.2, ΔN6-N (G) and ΔN6-I (H) at pH 6.2. The ΔN6-I mode dimers (and the strongly-matched dimers at pH 6.2) highlight the involvement of strand A of one of the monomers in dimerization and the intrinsic possibility of further oligomerization via the second monomer's solvent-exposed strand A. If the unstructured strands A of both monomers are involved in dimerization (as in the strongly-packed dimer at pH 7.2, F) further growth is still possible via the highly solvent-exposed and aromatic-rich DE-loops (highlighted in green). In ΔN6-N the AB-loop and the “unstructured” DE-loop (which is detached from the protein's core and exposed to the solvent) account for the possibility of further oligomerization. Other examples of ΔN6-I ‘mode’ dimers are reported in <b><a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003606#pcbi.1003606.s003" target="_blank">Fig. S3C</a></b> and <b><a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003606#pcbi.1003606.s003" target="_blank">Fig. S3D</a></b>. (I) Pictorial representation of monomers of ΔN6-I that were packed ‘by hand’ to indicate a possible oligomerization pattern leading to amyloid fibrils.