01431nas a2200157   4500008004100000022001400041245008300055210006900138260007300207300001200280490000800292520082000300100002501120700001501145856011301160       2011                        eng d  a0009-261400aEarly stages of unwinding of zwitterionic alpha-helical homopolymeric peptides0 aEarly stages of unwinding of zwitterionic alphahelical homopolym  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcOCT  a330-3350 v5143 a<p>Unwinding mechanisms of helices of the zwitterionic polyalanine, polyleucine, and polylysine were studied using classical molecular dynamics simulation at 300 K temperature. Interestingly the helices of polyalanine and polyleucine start to unwind from the terminals, which is further relayed to the middle of the chain with time. Polylysine helix also starts to unwind from the terminals of the alpha-helical chain but the unwinding is not relayed to the middle. The reason behind this observation is investigated whether the presence of -NH(2) groups in the side chain of polylysine is influencing the unwinding. Two competitive mechanisms, fluctuation of the terminal residues and exchange of H-bonds between residues and water trigger the process of unwinding. (C) 2011 Elsevier B. V. All rights reserved.</p>1 aPandey, Prithvi, Raj1 aRoy, Sudip  uhttp://library.ncl.res.in/content/early-stages-unwinding-zwitterionic-alpha-helical-homopolymeric-peptides-0