Structure of N-Acetylproline Amide in Liquid Water: Experimentally Measured and Numerically Simulated Infrared and Vibrational Circular Dichroism Spectra

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• 作者：Kyung-Koo Lee ; Seungsoo Hahn ; Kwang-Im Oh ; Jin Seok Choi ; Cheonik Joo ; Hochan Lee ; Hogyu Han ; Minhaeng Cho
• 刊名：Journal of Physical Chemistry B
• 出版年：2006
• 出版时间：September 28, 2006
• 年：2006
• 卷：110
• 期：38
• 页码：18834 - 18843
• 全文大小：407K
• 年卷期：v.110,no.38(September 28, 2006)
• ISSN：1520-5207

文摘

A few experimental and theoretical studies on the molecular structure of N-acetylproline amide (AP) in D₂Osolution have been reported recently. However, there is no consensus of the precise structure of AP in D₂Obecause spectroscopically determined structures and a theoretically simulated one have been found to bedifferent from one another. To determine its aqueous solution structure, IR and vibrational circular dichroismspectra of both L- and D-form AP solutions were measured. Molecular dynamics simulations with two differentforce fields and density functional theory calculations for the trans and cis rotamers of AP were performedto numerically simulate those spectra. Comparisons between experimentally measured and computationallysimulated spectra directly suggest that the AP in water adopts a polyproline II-like conformation and that theforce field parameter ff03 in the AMBER 8 suite of programs is more realistic and reliable in predictingmolecular structure of AP in water than the ff99 in AMBER 7.