Computational results characterizing the
structural properties
of Fmoc-Ala-Ala compared to Fmoc-Ala-Lac. In both systems, the number
of hydrogen bonds per molecule (A) and the solvent-accessible surface
area (SASA) (B) converge, indicating fibril stability. The non-normalized
radial distribution function (RDF) plots of the last 50 ns of each
simulation for the distance between the terminal residue’s
hydroxyl hydrogen and fibril axis (approximating the radius) (C) and
the distance between fluorenyl rings (D) show feature size similarity
between Fmoc-Ala-Ala and Fmoc-Ala-Lac systems. For the Fmoc-Ala-Lac
fibril assembly, a Ramachandran plot for the alanine (E) during the
last 50 ns of simulation shows a large population at (ϕ, ψ)
= (−70°, 164°) (indicative of polyproline-II conformation)
and a minor population at (ϕ, ψ) = (−70°,
−39°). The Ramachandran plot for the terminal Lac residue
(F) in Fmoc-Ala-Lac during the last 50 ns of simulation shows a large
population at (ϕ, ψ) = (−70°, −39°)
(indicative of an α-helix-like conformation) and a minor population
at (ϕ, ψ) = (−70°, 148°).