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Quasielastic light scattering investigation of the isothermal “helix to extended‐coil” transition of poly‐ L ‐lysine HBr
Author(s) -
Jamieson A. M.,
Mack L.,
Walton A. G.
Publication year - 1972
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1972.360111107
Subject(s) - chemistry , polymer , helix (gastropod) , crystallography , isotropy , scattering , anisotropy , isothermal process , aqueous solution , light scattering , folding (dsp implementation) , chemical physics , thermodynamics , optics , organic chemistry , ecology , physics , electrical engineering , snail , biology , engineering
The quasielastic light scattering of poly‐ L ‐lysine HBr in aqueous solutions has been examined over a variety of pH values where the polymer is in different conformations. Analysis of the spectra demonstrates that as the pH is lowered, the polymer changes from an extended anisotropic from through a collapsed randomized state to a larger isotropic form. These data support the current view that the polymer undergoes a conformational change from an α‐helical form to a “kinked” extended‐coil conformation through an intermediate partially α‐helical state in which internal packing of the helical portions occurs. Finally, a value for the rate of propagation of the unwinding of the α‐helix has been obtained.