The absence of an isotope effect on the stability of the poly‐β‐benzyl‐L‐aspartate α‐helix in aprotic solvents

Biopolymers - Tập 11 Số 8 - Trang 1745-1763 - 1972
Paul L. Dubin1, Frank E. Karasz1
1Polymer Science and Engineering University of Massachusetts Amherst , Massachusetts, 01002

Tóm tắt

Abstract

Optical rotatory dispersion measurements were used to follow the transition from the helical to the random coil conformation of poly‐β‐benzyl‐L‐aspartate as induced by changes in temperature and solvent composition in mixtures of dioxane and dimethylsulfoxide. Within experimental error, there is no difference in the stability of the helical state as measured in this way for the protonated and deuterated forms of the polypeptide. This result is considered in terms of previous attempts to study the isotope effect on conformational transitions of helical biological macromolecules and polypeptides. The conclusion is drawn that the apparent changes in conformational stability observed in these previous systems arise from alteration of the properties of the solvent. Speculations are advanced regarding the contribution of the interpeptide bond to the stability of the helical state.

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Tài liệu tham khảo

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Biopolymers

Tập 11 Số 8

1745-1763

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