Solution Properties of Synthetic Polypeptides. XIX. Heat Capacity Measurements on the System of Poly(ε-carbobenzyloxy-L-lysine) and m-Cresol in the Helix-Coil Transition Region

Nakamoto, K.; Suga, Hiroyuki; Seki, Shu; Teŕamoto, Akio; Norisuye, Takashi; Fujita, Hiroshi

doi:10.1021/ma60042a017

Cited by 14 publications

(2 citation statements)

References 3 publications

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“…It should be noted that the transition curves in [a] and Cs shown in Figures 3, 8, and 9 resemble closely those for thermal helix-coil transitions in polypeptides typical of linear cooperative systems. 5,18 Thus it is worthwhile to analyze the present data in terms of theories of helix-coil transitions in polypeptides. 5,19,20 This resemblance between the two phenomena suggests that fN correctly corresponds to helical content in the helix-coil transition.…”

Section: Discussionmentioning

confidence: 99%

Ordered structure in aqueous polysaccharide. 5. Cooperative order-disorder transition in aqueous schizophyllan

Itou¹,

Teŕamoto²,

Matsuo³

et al. 1986

Macromolecules

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Optical rotation and heat capacity measurements were made on aqueous solutions of schizophyllan, a triple-helical polysaccharide. T h e heat capacity data showed that aqueous schizophyllan, either isotropic or cholesteric, exhibited a sharp thermal transition located around 279 K, and the transition enthalpy per mole of the polysaccharide repeating unit (648.6 g) was (2.83 h 0.1) k J mol-' in H20 and 3.96 k J mol-' in D20.

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Section: Discussionmentioning

confidence: 99%

Ordered structure in aqueous polysaccharide. 5. Cooperative order-disorder transition in aqueous schizophyllan

Itou¹,

Teŕamoto²,

Matsuo³

et al. 1986

Macromolecules

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“…Cooperativity in a polymer transition can be verified through studies of corresponding oligomers, as has been done in the case of model polypeptides Nakamoto et al, 1974; Shaw & Schurr, 1975) and nucleic acids (Applequist & Damle, 1965; Martin et al, 1971; Nelson et al, 1981). We show here that the same approach can be used with polysaccharides.…”

mentioning

confidence: 54%

Double-stranded structure for hyaluronic acid in ethanol-aqueous solution as revealed by circular dichroism of oligomers

Staskus¹,

Johnson²

1988

Biochemistry

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The sigmoidal nature of circular dichroism (CD) changes for hyaluronic acid solutions as a function of solvent composition or temperature is studied as a function of chain length by using oligomers. We find a chain length effect with approximately nine disaccharides required for the structural transition as a function of organic solvent, which proves that the transition is cooperative with large transition enthalpy and entropy. The transition also depends on sample concentration as expected for strand association, and this was investigated in detail for oligomers 12 and 16 disaccharides long. Indeed, it was possible to prevent completely the transition in mixed solvent with sufficient dilution of these oligomers, which demonstrates strand association. The CD data in mixed solvent as a function of oligomer concentration were fit with various models for association of two and more strands. Simplex methods were used to investigate the vector space of unknowns for the models, and two-strand models were shown to consistently give a better fit. A cooperative two-strand zipper model which allows relative sliding of the chains had the smallest fitting error and produced the following thermodynamic parameters (in terms of a duplex of disaccharide units) for the ordered structure in an aqueous solution containing 45% v/v ethanol, 12.5 mM NaH2PO4, and 7.5 mM H3PO4: enthalpy of growth, -1.0 +/- 0.3 kcal mol-1; entropy of growth, -2.3 +/- 1.3 eu mol-1; enthalpy of initiation, -20 +/- 3 kcal mol-1; entropy of initiation, -71 +/- 15 eu mol-1. The results are consistent with a double-stranded and helical structure for hyaluronic acid in solutions of reduced dielectric constant.

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Solution properties of synthetic polypeptiedes. XXI. Solvent effect on the helix‐coil transition of poly(e‐carbobenzoxy L‐lysine)

1978

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SynopsisHelix-coil transitions of poly(c-carbobenzoxy L-lysine) in mixtures of dichloroacetic acid and 1,2-dichloroethane were investigated by optical rotatory dispersion (ORD) measurements. The ORD data were analyzed according to the statistical mechanical approaches developed by Sayama et al. (1970) (Ref. 10) and by Karasz and Gajnos (1973) (Ref. 4) to obtain the enthalpy change associated with the unfolding of helix in the inert solvent 1,2-dichloroethane, &Yo, and that for the solvation of the peptide backbone with the dichloroacetic acid dimer, AHn. The results were: A H 0 = -(340 -620) cal/mol and AHn = -(2.4 -3.6) kcal/mol. These values are favorably compared with those for poly(y-benzyl L-glutamate) and poly(/3-benzyl L-aspartate) in the same solvent system. On the other hand, the equilibrium constant for the solvation and the cooperativity parameter in the inert solvent 1,2-dichloroethane depended appreciably on the chemical structure of the side chain. In terms of the Zimm-Bragg parameter, s, which varied from 1.3 to 1.7 with polypeptide species, the helices of these three polypeptides are far from complete even in the typical helix-supporting solvent 1.2-dichloroethane.

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Solution Properties of Synthetic Polypeptides. XIX. Heat Capacity Measurements on the System of Poly(ε-carbobenzyloxy-L-lysine) and m-Cresol in the Helix-Coil Transition Region

Cited by 14 publications

References 3 publications

Ordered structure in aqueous polysaccharide. 5. Cooperative order-disorder transition in aqueous schizophyllan

Ordered structure in aqueous polysaccharide. 5. Cooperative order-disorder transition in aqueous schizophyllan

Double-stranded structure for hyaluronic acid in ethanol-aqueous solution as revealed by circular dichroism of oligomers

Solution properties of synthetic polypeptiedes. XXI. Solvent effect on the helix‐coil transition of poly(e‐carbobenzoxy L‐lysine)

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