### Abstract

Monte Carlo simulations of a small protein, carmbin, were carried out with and without hydration energy. The methodology presented here is characterized, as compared with the other similar simulations of proteins in solution, by two points: (1) protein conformations are treated in fixed geometry so that dihedral angles are independent variables rather than cartesian coordinates of atoms; and (2) instead of treating water molecules explicitly in the calculation, hydration energy is incorporated in the conformational energy function in the form of Σg_{i}A_{i}, where A_{i} is the accessible surface area of an atomic group i in a given conformation, and g_{i} is the free energy of hydration per unit surface area of the atomic group (i.e., hydration-shell model). Reality of this model was tested by carrying out Monte Carlo simulations for the two kinds of starting conformations, native and unfolded ones, and in the two kinds of systems, in vacuo and solution. In the simulations starting from the native conformation, the differences between the mean properties in vacuo and solution simulations are not very large, but their fluctuations around the mean conformation during the simulation are relatively smaller in solution than in vacuo. On the other hand, in the simulations starting from the unfolded conformation, the molecule fluctuates much more largely in solution than in vacuo, and the effects of taking into account the hydration energy are pronounced very much. The results suggest that the method presented in this paper is useful for the simulations of proteins in solution.

Original language | English |
---|---|

Pages (from-to) | 733-747 |

Number of pages | 15 |

Journal | Journal of Protein Chemistry |

Volume | 8 |

Issue number | 6 |

DOIs | |

Publication status | Published - 1989 Dec |

### Fingerprint

### Keywords

- conformational energy analysis
- crambin
- hydration energy
- Monte Carlo simulation

### ASJC Scopus subject areas

- Biochemistry

### Cite this

**Monte Carlo simulations of a protein molecule with and without hydration energy calculated by the hydration-shell model.** / Wako, Hiroshi.

Research output: Contribution to journal › Article

}

TY - JOUR

T1 - Monte Carlo simulations of a protein molecule with and without hydration energy calculated by the hydration-shell model

AU - Wako, Hiroshi

PY - 1989/12

Y1 - 1989/12

N2 - Monte Carlo simulations of a small protein, carmbin, were carried out with and without hydration energy. The methodology presented here is characterized, as compared with the other similar simulations of proteins in solution, by two points: (1) protein conformations are treated in fixed geometry so that dihedral angles are independent variables rather than cartesian coordinates of atoms; and (2) instead of treating water molecules explicitly in the calculation, hydration energy is incorporated in the conformational energy function in the form of ΣgiAi, where Ai is the accessible surface area of an atomic group i in a given conformation, and gi is the free energy of hydration per unit surface area of the atomic group (i.e., hydration-shell model). Reality of this model was tested by carrying out Monte Carlo simulations for the two kinds of starting conformations, native and unfolded ones, and in the two kinds of systems, in vacuo and solution. In the simulations starting from the native conformation, the differences between the mean properties in vacuo and solution simulations are not very large, but their fluctuations around the mean conformation during the simulation are relatively smaller in solution than in vacuo. On the other hand, in the simulations starting from the unfolded conformation, the molecule fluctuates much more largely in solution than in vacuo, and the effects of taking into account the hydration energy are pronounced very much. The results suggest that the method presented in this paper is useful for the simulations of proteins in solution.

AB - Monte Carlo simulations of a small protein, carmbin, were carried out with and without hydration energy. The methodology presented here is characterized, as compared with the other similar simulations of proteins in solution, by two points: (1) protein conformations are treated in fixed geometry so that dihedral angles are independent variables rather than cartesian coordinates of atoms; and (2) instead of treating water molecules explicitly in the calculation, hydration energy is incorporated in the conformational energy function in the form of ΣgiAi, where Ai is the accessible surface area of an atomic group i in a given conformation, and gi is the free energy of hydration per unit surface area of the atomic group (i.e., hydration-shell model). Reality of this model was tested by carrying out Monte Carlo simulations for the two kinds of starting conformations, native and unfolded ones, and in the two kinds of systems, in vacuo and solution. In the simulations starting from the native conformation, the differences between the mean properties in vacuo and solution simulations are not very large, but their fluctuations around the mean conformation during the simulation are relatively smaller in solution than in vacuo. On the other hand, in the simulations starting from the unfolded conformation, the molecule fluctuates much more largely in solution than in vacuo, and the effects of taking into account the hydration energy are pronounced very much. The results suggest that the method presented in this paper is useful for the simulations of proteins in solution.

KW - conformational energy analysis

KW - crambin

KW - hydration energy

KW - Monte Carlo simulation

UR - http://www.scopus.com/inward/record.url?scp=0024893329&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0024893329&partnerID=8YFLogxK

U2 - 10.1007/BF01024898

DO - 10.1007/BF01024898

M3 - Article

C2 - 2624684

AN - SCOPUS:0024893329

VL - 8

SP - 733

EP - 747

JO - Protein Journal

JF - Protein Journal

SN - 1572-3887

IS - 6

ER -