In
this work, nanomembranes formed by the I3
XGK (X = Q, S, or N) polar peptides are studied to characterize the average force and
energy required to separate two neighboring β-sheets laterally
joined by polar zippers. The results presented are obtained using
a methodology (state of the art) involving the pulling umbrella method
to generate the samples (umbrella sampling) and the potential of mean
force (PMF) to evaluate the energetic variation evolved in the process
of separating the polar zipper. It was observed that the maximum force
required to separate the regions linked by polar zippers is 1.48 kJ/mol
nm for the I3
NGK nanomembrane and 1.22 kJ/mol
nm [1.30 kJ/mol nm] for the I3
QGK [I3
SGK] nanomembranes, emphasizing that polar zippers play
an important role in the interaction that interconnects β-sheets
in broad and robust two-dimensional structures (tapes and membranes),
offering an agile route to the construction of distinct nanomaterials
from β-sheets. Also, negative values were obtained for energy
as a function of the reaction coordinate for the regions where the
formation of polar zippers occurs, showing that the lateral union
of neighboring β-sheets is energetically favorable, with a value
up to −3.0 kJ/mol, in the case of I3
NGK nanomembranes.