کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5183399 1381017 2010 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Mechanism of the screw-sense reversal of tightly hydrogen-bonded α-helical network triggered by the side-chain conformation
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Mechanism of the screw-sense reversal of tightly hydrogen-bonded α-helical network triggered by the side-chain conformation
چکیده انگلیسی

The paper presents theoretical treatment of a screw-sense reversal of tightly hydrogen-bonded α-helical polypeptide chains. The transition is triggered by the conformational free-energy difference (s) of the side chain flanking the chiral (right(r)- or left(ℓ)-handed) backbone. The two-parameter scheme (s, σ) corresponding to a zipper-type transition model starting from one terminal has been constructed and applied to the thermally-induced helix-helix transition characteristic of polyaspartic acid esters observed in the helicoidal solution. The weighting parameter σ takes care of the instability associated with the ℓ/r junction, i.e., the unfolded site where at least three successive hydrogen-bonds should become free to change their partner. The enthalpy of transition (ca. 2 kJ/mol) of poly(β-phenethyl l-aspartate) (PPLA) (Mv = 6 × 104) observed in the lyotropic liquid crystalline state in 1,1,2,2-tetrachloroethane has been reproduced with the instability parameter σ = 0.001-0.0001. Attempts were further extended to interpret the thermally-induced helix-helix transition behaviors of the PPLA homopolymers and random copolymers involving benzyl l-aspartate residues observed under various conditions.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 51, Issue 26, 10 December 2010, Pages 6234-6239
نویسندگان
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