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Chain‐length dependence of α‐helix to β‐sheet transition in polylysine: Model of protein aggregation studied by temperature‐tuned FTIR spectroscopy
Author(s) -
Dzwolak Wojciech,
Muraki Takeshi,
Kato Minoru,
Taniguchi Yoshihiro
Publication year - 2004
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.10582
Subject(s) - antiparallel (mathematics) , chemistry , crystallography , beta sheet , polylysine , helix (gastropod) , fourier transform infrared spectroscopy , protein secondary structure , spectroscopy , stereochemistry , side chain , protein structure , polymer , organic chemistry , biochemistry , ecology , physics , quantum mechanics , snail , magnetic field , biology
The chain‐length dependence of the α‐helix to β‐sheet transition in poly( L ‐lysine) is studied by temperature‐tuned FTIR spectroscopy. This study shows that heterogeneous samples of poly( L ‐lysine), comprising polypeptide chains with various lengths, undergo the α–β transition at an intermediate temperature compared to homogenous ingredients. This holds true as long as each individual fraction of the polypeptide is capable of adopting an antiparallel β‐sheet structure. The tendency is that the longer chain is, the lower the α–β transition temperature is, which has been linked to the presence of distorted or solvated helices with turns or β sheets in elongating chains of poly( L ‐lysine). As such helical structures are apparently conducive to the α–β transition, this draws a comparison to the hypothesis of metastable protein conformational states being a common stage in amyloid‐formation pathways. The antiparallel architecture of the β sheet is likely to reflect the pretransition interhelical interactions in poly( L ‐lysine). Namely, the chains are arranged in an antiparallel manner because of energetically favored antiparallel preassembly of dipolar α helices. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004