01231nas a2200157   4500008004100000022001400041245013700055210006900192260007100261300001400332490000700346520055000353100002200903700002400925856012400949       2010                        eng d  a1523-706000aWater-induced switching of beta-structure to polyproline II conformation in the 4s-aminoproline polypeptide via H-bond rearrangement0 aWaterinduced switching of betastructure to polyproline II confor  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcDEC  a5390-53930 v123 a<p>4S-Aminoproline polypeptide 2 forms unusual beta-structure in trifluoroethanol that switches to the polyproline II (PPII) form in aqueous medium. while 4R-aminoproline peptide 1 retains PPII form in both solvents. This first instance of a polyproline derivative showing a beta-structure is attributed to competitive pH-dependent (4-NH3+/NH2) stereoelectronic effect (4R vs 4S) and the overriding importance of stercospecific intra/intermolecular H-bonding in (2,4)-cis-4S-aminoproline in contrast to (2,4)-trans-4R-aminoproline oligomers.</p>1 aSonar, Mahesh, V.1 aGanesh, Krishna, N.  uhttps://library.ncl.res.in/content/water-induced-switching-beta-structure-polyproline-ii-conformation-4s-aminoproline-0