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Kinetics of coil to α‐helix to β‐structure transitions of poly( L ‐ornithine) in low concentrations of sodium dodecyl sulfate
Author(s) -
Takeda Kunio
Publication year - 1985
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.360240408
Subject(s) - chemistry , sodium dodecyl sulfate , helix (gastropod) , kinetics , crystallography , sodium , chromatography , organic chemistry , ecology , physics , quantum mechanics , snail , biology
Conformational changes of poly(L‐ornithine) [(Orn) n ] were studied in a sodium dodecyl sulfate (NaDodSO 4 ) solution by CD. (Orn) n adopted an unstable and a stable helical structure below and above the NaDodSO 4 concentration range where β‐structure was favored, respectively. CD stopped‐flow was used to monitor the transitions from coil to the unstable helix, from the helix to β‐structure, and from coil to β‐structure. Only the rate of the helix to β‐structure transition was accelerated by an increase in NaDodSO 4 concentration, whereas the rates of the others were independent of NaDodSO 4 concentration. The fractions of coil, α‐helix, and β‐structure in each conformation of (Orn) n caused by NaDodSO 4 were computed by simulating a mixed spectrum of typical CD spectra for these structures to the experimentally obtained spectrum. The contents of the unstable and stable helical structures were less than 50 and 73%, respectively.