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Effect of temperature and pH on the β–helix transition of poly( L ‐lysine) in sodium dodecyl sulfate solution
Author(s) -
Satake Iwao,
Yang Jen Tsi
Publication year - 1975
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.1975.360140906
Subject(s) - chemistry , sodium dodecyl sulfate , lysine , circular dichroism , helix (gastropod) , sodium , sulfate , inorganic chemistry , crystallography , chromatography , organic chemistry , amino acid , biochemistry , ecology , biology , snail
The conformational phase diagram of poly( L ‐lysine) (4.6 × 10 −4 M , residue) in sodium dodecyl sulfate (1.6 × 10 −2 M ) solution was constructed from circular dichroism results at various temperatures and pH's. Poly( L ‐lysine)–sodium dodecyl sulfate complexes undergo a β–helix transition upon raising the pH of the solution. The transition pH tends to shift downward at elevated temperatures. No helix–β transition can be detected for poly( L ‐lysine) in sodium dodecyl sulfate solution (pH > 11) even after 1‐hr heating at 70°C. This is in marked contrast with uncharged poly( L ‐lysine) solution without sodium dodecyl sulfate, which is converted into the β‐form upon mild heating of the solution above 50°C.