Valdeavella C V, Blatt H D, Pettitt B M
Department of Chemistry, University of Houston, Texas, USA.
Int J Pept Protein Res. 1995 Nov;46(5):372-80. doi: 10.1111/j.1399-3011.1995.tb01071.x.
The conformational properties of the configurational isomers of tuftsin, a linear tetrapeptide with the sequence Thr-Lys-Pro-Arg, were investigated with six 1 ns molecular dynamics simulations in explicit water and in a 1.0 m NaCl solution. The average conformation of the cis isomer is a type VI beta-turn. Our results indicate that water-peptide hydrogen bonding, in addition to intramolecular hydrogen bonds, stabilizes the cis conformer. The trans isomer is neither a beta- nor a gamma-turn. Results are compared with parallel studies on a cyclic analog of tuftsin, cyclo(Thr-Lys-Pro-Arg-Gly). The addition of salt does, not influence the backbone conformation of the peptide. Differences between the structures are confined to the side-chain orientations of the Lys and Arg residues.
采用六个1纳秒的分子动力学模拟，在纯水和1.0 M NaCl溶液中研究了促吞噬肽（一种序列为苏氨酸-赖氨酸-脯氨酸-精氨酸的线性四肽）构型异构体的构象性质。顺式异构体的平均构象为VI型β-转角。我们的结果表明，除了分子内氢键外，水-肽氢键也稳定了顺式构象体。反式异构体既不是β-转角也不是γ-转角。将结果与对促吞噬肽的环状类似物环（苏氨酸-赖氨酸-脯氨酸-精氨酸-甘氨酸）的平行研究进行了比较。盐的添加不影响肽的主链构象。结构之间的差异仅限于赖氨酸和精氨酸残基的侧链取向。
