### Abstract

Results of an application of integral equation theory to the determination of the intramolecular potential of mean force for the alanine dipeptide. N-methyl alanine acetamide, in aqueous solution are presented. The calculations are based on Ornstein-Zernike-like equations for polar systems with an intramolecular superposition approximation. The solvated free energy surface for the dipeptide as a function of the dihedral angles φ and ψ (Ramachandran plot) is determined and compared with the vaccum surface calculations. Conformations that are essentially forbidden in vaccum are found to be significant in aqueous solution. The solvent contributions to the free energy surface are decomposed into enthalpic and entropic terms. Possible applications and extensions of the method are outlined.

Original language | English (US) |
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Pages (from-to) | 194-201 |

Number of pages | 8 |

Journal | Chemical Physics Letters |

Volume | 121 |

Issue number | 3 |

DOIs | |

State | Published - Nov 8 1985 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Physical and Theoretical Chemistry
- Spectroscopy
- Condensed Matter Physics
- Atomic and Molecular Physics, and Optics
- Surfaces and Interfaces

### Cite this

**The potential of mean force surface for the alanine dipeptide in aqueous solution : a theoretical approach.** / Pettitt, Bernard; Karplus, Martin.

Research output: Contribution to journal › Article

*Chemical Physics Letters*, vol. 121, no. 3, pp. 194-201. https://doi.org/10.1016/0009-2614(85)85509-3

}

TY - JOUR

T1 - The potential of mean force surface for the alanine dipeptide in aqueous solution

T2 - a theoretical approach

AU - Pettitt, Bernard

AU - Karplus, Martin

PY - 1985/11/8

Y1 - 1985/11/8

N2 - Results of an application of integral equation theory to the determination of the intramolecular potential of mean force for the alanine dipeptide. N-methyl alanine acetamide, in aqueous solution are presented. The calculations are based on Ornstein-Zernike-like equations for polar systems with an intramolecular superposition approximation. The solvated free energy surface for the dipeptide as a function of the dihedral angles φ and ψ (Ramachandran plot) is determined and compared with the vaccum surface calculations. Conformations that are essentially forbidden in vaccum are found to be significant in aqueous solution. The solvent contributions to the free energy surface are decomposed into enthalpic and entropic terms. Possible applications and extensions of the method are outlined.

AB - Results of an application of integral equation theory to the determination of the intramolecular potential of mean force for the alanine dipeptide. N-methyl alanine acetamide, in aqueous solution are presented. The calculations are based on Ornstein-Zernike-like equations for polar systems with an intramolecular superposition approximation. The solvated free energy surface for the dipeptide as a function of the dihedral angles φ and ψ (Ramachandran plot) is determined and compared with the vaccum surface calculations. Conformations that are essentially forbidden in vaccum are found to be significant in aqueous solution. The solvent contributions to the free energy surface are decomposed into enthalpic and entropic terms. Possible applications and extensions of the method are outlined.

UR - http://www.scopus.com/inward/record.url?scp=33947669512&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33947669512&partnerID=8YFLogxK

U2 - 10.1016/0009-2614(85)85509-3

DO - 10.1016/0009-2614(85)85509-3

M3 - Article

AN - SCOPUS:33947669512

VL - 121

SP - 194

EP - 201

JO - Chemical Physics Letters

JF - Chemical Physics Letters

SN - 0009-2614

IS - 3

ER -