Biological activity for most living organisms is at its highest where the percolation
transition occurs hence finding such temperature range was of utmost importance. After having
found such temperature interval i.e. between 310K and 330K conformational studies were
performed on full-length human and rat islet amyloid polypeptide hIAPP and rIAPP respectively
by MD simulations both for the reduced and oxidized IAPP moieties. Studying the monomeric forms
of two very similar polypetides that present different amyloidogenic properties could shed
light on the aggregation mechanism of human islet amyloid polypeptide in fact after hundreds
of nanoseconds above the percolation transition temperature oxidized hIAPP 'folded 'into a
compact structure that was about 10% smaller than the average value of the radius of gyration.
Further studies were carried out on some in silico mutated hIAPP moieties in order to pinpoint
key residues involved in the 'folding' of hIAPP. Three conditions were needed in order to
observe this compact state: the presence of the disulfide bond the absence of the P28 residue
found in rat IAPP presence of aromatic residues in particular F23.
