Nonlinear elasticity of an alpha-helical polypeptide

@article{citeulike:970343, abstract = {We study a minimal extension of the wormlike chain model to describe polypeptides having -helical secondary structure. In this model the presence or absence of secondary structure enters as a scalar variable that controls the local chain bending modulus. Using this model we compute the extensional compliance of an -helix under tensile stress, the bending compliance of the molecule under externally imposed torques, and the nonlinear interaction of such torques and forces on the molecule. We find that, due to coupling of the \"internal\" secondary structure variables to the conformational degrees of freedom of the polymer, the molecule has a highly nonlinear response to applied stress and force couples. In particular we demonstrate a sharp lengthening transition under applied force and a buckling transition under applied torque. Finally, we speculate that the inherent bistability of the molecule may underlie protein conformational change in vivo.}, author = {Chakrabarti, Buddhapriya and Levine, Alex J. }, citeulike-article-id = {970343}, doi = {10.1103/PhysRevE.71.031905}, journal = {Physical Review E (Statistical, Nonlinear, and Soft Matter Physics)}, number = {3}, posted-at = {2006-12-01 12:45:58}, priority = {2}, publisher = {APS}, title = {Nonlinear elasticity of an alpha-helical polypeptide}, url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal\&id=PLEEE8000071000003031905000001\&idtype=cvips\&gifs=yes}, volume = {71}, year = {2005} }

TY - JOUR ID - citeulike:970343 L3 - citeulike-article-id:970343 TI - Nonlinear elasticity of an alpha-helical polypeptide JF - Physical Review E (Statistical, Nonlinear, and Soft Matter Physics) VL - 71 IS - 3 PB - APS N2 - We study a minimal extension of the wormlike chain model to describe polypeptides having -helical secondary structure. In this model the presence or absence of secondary structure enters as a scalar variable that controls the local chain bending modulus. Using this model we compute the extensional compliance of an -helix under tensile stress, the bending compliance of the molecule under externally imposed torques, and the nonlinear interaction of such torques and forces on the molecule. We find that, due to coupling of the "internal" secondary structure variables to the conformational degrees of freedom of the polymer, the molecule has a highly nonlinear response to applied stress and force couples. In particular we demonstrate a sharp lengthening transition under applied force and a buckling transition under applied torque. Finally, we speculate that the inherent bistability of the molecule may underlie protein conformational change in vivo. AU - Chakrabarti, Buddhapriya AU - Levine, Alex PY - 2005/// UR - http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PLEEE8000071000003031905000001&idtype=cvips&gifs=yes ER -