Formation of helical states in wormlike polymer chains

We propose a potential for wormlike polymer chains which could be used to model the low-temperature polypeptide structures. We successfully reproduced helix ground states up to 6.5 helical loops, using the multicanonical Monte Carlo simulation method. We demonstrate that the coil-helix transition involves four distinct states: coil (gaslike), collapsed globular (liquidlike), and two helical states I and II (both solidlike). The helix I state is characterized by a helical ordering with dangling loose ends, and the helix II state corresponds to a near-perfect helical ordering in the entirely crystallized chain. [S0031-9007(98)07574-7].