Plant Polypeptide Hormone Systemin Prefers Polyproline II Conformation in Solution

In this work, we carry out new time-dependent density functional theory calculations on the cationic tripeptide GAG in implicit and explicit water to determine the transitions that give rise to the observed CD signals of polyproline II and β-strand conformations. Our results reveal a plethora of electronic transitions that are governed by configurational interactions between multiple molecular orbital transitions of comparable energy. We also show that reproducing the CD spectra of polyproline II and β-strand conformations requires the explicit consideration of water molecules. The structure dependence of delocalized occupied orbitals contributes to the experimentally-observed invalidation of Flory’s isolated pair hypothesis.

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A New Interpretation of the Structure and Solvent Dependence of the Far UV Circular Dichroism Spectrum of Short Oligopeptides

10.26434/chemrxiv.8028134 ◽

2019 ◽

Author(s):

Anshuman Kumar ◽

Reinhard Schweitzer-Stenner ◽

Bryan Wong

Keyword(s):

Density Functional ◽

Density Functional Theory Calculations ◽

Cd Spectra ◽

Functional Theory ◽

Polyproline Ii ◽

Solvent Dependence ◽

Explicit Consideration ◽

New Interpretation ◽

Implicit And Explicit ◽

Explicit Water

In this work, we carry out new time-dependent density functional theory calculations on the cationic tripeptide GAG in implicit and explicit water to determine the transitions that give rise to the observed CD signals of polyproline II and β-strand conformations. Our results reveal a plethora of electronic transitions that are governed by configurational interactions between multiple molecular orbital transitions of comparable energy. We also show that reproducing the CD spectra of polyproline II and β-strand conformations requires the explicit consideration of water molecules. The structure dependence of delocalized occupied orbitals contributes to the experimentally-observed invalidation of Flory’s isolated pair hypothesis.

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Polypeptide Hormone Interaction

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)44928-4 ◽

1972 ◽

Vol 247 (16) ◽

pp. 4986-4991 ◽

Cited By ~ 1

Author(s):

Arthur B. Schneider ◽

Harold Edelhoch

Keyword(s):

Polypeptide Hormone ◽

Hormone Interaction

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Assessing backbone solvation effects in the conformational propensities of amino acid residues in unfolded peptides

Physical Chemistry Chemical Physics ◽

10.1039/c5cp03646a ◽

2015 ◽

Vol 17 (38) ◽

pp. 24917-24924 ◽

Cited By ~ 27

Author(s):

Niranjan V. Ilawe ◽

Alexandra E. Raeber ◽

Reinhard Schweitzer-Stenner ◽

Siobhan E. Toal ◽

Bryan M. Wong

Keyword(s):

Amino Acid ◽

Amino Acid Residues ◽

Solvation Effects ◽

Self Energy ◽

Polyproline Ii ◽

Water Water Water

Large energetic contributions to the stabilization of polyproline II result from peptide–water, water–water interactions, and changes of the solvent self-energy.

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