Theoretical study on the structural variations of alanine dipeptide conformers by hydration수화에 의한 알라닌-다이펩티드 이형태체들의 구조변화에 관한 이론적 연구

The effects in structural variations and relative stabilities of the hydration of Alanine dipeptide in the $C^{eq}_7$, $C^{ax}_7$, $C_5$, $\alpha_R$, and $P_{II}$ conformations were investigated by the method of SUMSL(Secant-type Unconstrained minimization Solver) energy Minimization technique with the empirical four-term potential energy function of the solute, and with the ST2 water model. We thought the hydration, imaginarily, as the discrete addition of water molecules to the solute. The binding sites of water molecules in the solute are selected from spherical interaction energy maps. As a function of the number of added water molecules, we traced the structural variations mainly in the (Φ,Ψ) torsion angle space, and calculated the total internal energies of each solute-waters systems to evaluate the relative probabilities between those five conformers. The results indicate that the conformers having no intramolecular hydrogen-bondings, such as $\alpha_R$, $C_5$, $P_{II}$, show larger structural variations than the conformers of $C^{ax}_7$, $C^{eq}_7$ which have intramolecular hydrogen-bondings. The torsion angle of Ψ fluctuated more than Φ for all the examined conformers. Probably this fact was caused by the presence of the repulsive interaction over the dihedral angle of $C_\beta^-C_\alpha^-C``_R-O_R$ in the solute. The energetically dominant conformation is shifted from $C^{eq}_7$ to $\alpha_R$ as the hydration is proceeded.
Advisors
Jhon, Mu-Shik(전무식)researcher
Publisher
한국과학기술원
Issue Date
1991
Identifier
67627/325007 / 000891273
Language
eng
Description

학위논문(석사) - 한국과학기술원 : 화학과, 1991.2, [ iv, 38 p. ]

URI
http://hdl.handle.net/10203/32597
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=67627&flag=t
Appears in Collection
CH-Theses_Master(석사논문)
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