Conformational change of L-phenylalanine in fluorinated alcohol-water mixed solvents studied by IR, NMR, and MD simulations
Conformational change of L-phenylalanine in fluorinated alcohol-water mixed solvents studied by IR, NMR, and MD simulations
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通过 IR、NMR 和 MD 模拟研究 L-苯丙氨酸在氟化醇-水混合溶剂中的构象变化
DOI：
10.1016/j.molliq.2019.111192
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发表时间：
2019
影响因子：
6
通讯作者：
To Takahiro，Mizusaki Hiroaki，Murai Asami，Matsugami Masaru，Takamuku Toshiyuki
中科院分区：
文献类型：
--
作者：
Seigo Ohno;Katsuhiko Miyamoto;Shin’ichiro Hayashi;Norihiko Sekine;To Takahiro，Mizusaki Hiroaki，Murai Asami，Matsugami Masaru，Takamuku Toshiyuki
为了阐明1，1，1，3，3，3-六氟异丙醇在L-苯丙氨酸(Phe)生物分子上的独特溶剂化性质，用分子动力学(MD)模拟方法，在70 dm−3的混合溶剂中，观察了六氟异丙醇在HFIP摩尔分数范围内的溶剂化结构。比较了苯丙氨酸在HFIP溶剂和异丙醇-水混合溶剂中的溶剂化结构，以及L亮氨酸在乙醇-水混合溶剂中的溶剂化结构。红外光谱、核磁共振和分子动力学模拟的结果表明，随着HFIP的增加，与Phe羧酸基形成氢键的水分子逐渐被HFIP取代。相反，在苯胺基上用HFIP取代水分子不容易发生。这些发现源于HFIP羟基的电子可接受性高，而由于六个氟原子的电子吸引，HFIP羟基的电子迁移率很低。在2-ProH溶液中，由于2-ProH的电子可接受性较低，随着x2-PrOH的增加，2-ProH较不容易被2-ProH取代。Phe亲水部分的溶剂化程度与Leu相似。HFIP和2-ProH的最大区别在于苯基的溶剂化。随着两种醇溶液中乙醇含量的增加，苯基周围的疏水水合壳发生坍塌。而不是水，HFIP氟原子显著地与苯基氢原子相互作用，而2-PROH分子不显著地接近氢原子。Phe分子的构象与Cγ-Cβ-Cα-CoO−的二面角变化随HFIP含量的增加而发生变化，但不随2-ProH的增加而变化。这归因于HFIP分子显著溶剂化的大苯基和羧酸基之间的空间位阻。
To clarify the unique solvation properties of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) on a biomolecule of L-phenylalanine (Phe), the solvation structure of Phe in HFIP-water mixed solvents at 70 mmol dm−3has been observed over the entire range of HFIP mole fractionxHFIPusing infrared (IR),1H and13C NMR techniques with a help of molecular dynamics (MD) simulation. The solvation structure of Phe in the HFIP solvents has been compared with that in 2-propanol (2-PrOH)-water mixed solvents and the structure of L-leucine (Leu) in both alcohol-water mixed solvents previously reported. The results from IR, NMR, and MD simulations showed that water molecules hydrogen-bonded with the Phe carboxylate group are gradually replaced by HFIP with increasingxHFIP. In contrast, the replacement of water molecules by HFIP on the Phe aminium group does not easily take place. These findings arise from the high electron acceptability and the very low electron donicity of the HFIP hydroxyl group due to the electron drawing of the six fluorine atoms. In the 2-PrOH solutions, the replacement of water on the carboxylate group by 2-PrOH less easily occurs with increasingx2-PrOHcompared to HFIP because of the lower electron acceptability of 2-PrOH. The solvation for the Phe hydrophilic parts is similar to that of Leu. The most significant difference between HFIP and 2-PrOH was observed for the solvation of the Phe phenyl group. The hydrophobic hydration shell around the phenyl group is collapsed with increasing alcohol content in both alcohol solutions. Instead of water, the HFIP fluorine atoms significantly interact with the phenyl hydrogen atoms, whereas 2-PrOH molecules do not markedly approach the hydrogen atoms. The conformational change of Phe molecule against the dihedral angle of Cγ-Cβ–Cα-COO−takes place with increasing HFIP content, but does not with the increase in 2-PrOH. This is attributed to the steric hindrance between the large phenyl group and the carboxylate group remarkably solvated by HFIP molecules.
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影响因子：
2.9
作者：
Adhikari, Upendra;Scheiner, Steve
通讯作者：
Scheiner, Steve
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DOI：
--
发表时间：
2004
期刊：
Activity Report on Neutron Scattering Research 11
影响因子：
--
作者：
T.Takamuku;Y;Umebayashi et al.
通讯作者：
Umebayashi et al.
影响因子：
6.3
作者：
BERENDSEN, HJC;VANDERSPOEL, D;VANDRUNEN, R
通讯作者：
VANDRUNEN, R
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影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
Jiang, L;Lai, LH
通讯作者：
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