Canalia Muriel, Malliavin Thérèse E, Kremer Werner, Kalbitzer Hans R
Laboratoire de Biochimie Théorique, CNRS UPR 9080, Institut de Biologie Physico-Chimique, Paris, France.
Biopolymers. 2004 Aug 5;74(5):377-88. doi: 10.1002/bip.20089.
The histidine-containing protein (HPr) plays an important role in the phosphotransferase system (PTS). The deformations induced on the protein structure at high hydrostatic pressure values (4, 50, 100, 150, and 200 MPa) were previously (H. Kalbitzer, A. Görler, H. Li, P. Dubovskii, A. Hengstenberg, C. Kowolik, H. Yamada, and K. Akasaka, Protein Science 2000, Vol. 9, pp. 693-703) analyzed by NMR experiments: the nonlinear variations of the amide chemical shifts at high pressure values were supposed to arise from induced shifts in the protein conformational equilibrium. Molecular dynamics (MD) simulations are here performed, to analyze the protein internal mobility at 0.1 MPa, and to relate the nonlinear variations of chemical shifts observed at high pressure, to variations in conformational equilibrium. The global features of the protein structure are only slightly modified along the pressure. Nevertheless, the values of the Voronoi residues volumes show that the residues of alpha-helices are more compressed that those belonging to the beta-sheet. The alpha-helices are also displaying the largest internal mobility and deformation in the simulations. The nonlinearity of the 1H chemical shifts, computed from the MD simulation snapshots, is in qualitative agreement with the nonlinearity of the experimentally observed chemical shifts.
含组氨酸蛋白（HPr）在磷酸转移酶系统（PTS）中发挥着重要作用。先前（H. Kalbitzer、A. Görler、H. Li、P. Dubovskii、A. Hengstenberg、C. Kowolik、H. Yamada和K. Akasaka，《蛋白质科学》2000年，第9卷，第693 - 703页）通过核磁共振实验分析了在高静水压力值（4、50、100、150和200兆帕）下蛋白质结构所诱导的变形：高压值下酰胺化学位移的非线性变化被认为源于蛋白质构象平衡的诱导位移。本文进行了分子动力学（MD）模拟，以分析0.1兆帕下蛋白质的内部流动性，并将高压下观察到的化学位移的非线性变化与构象平衡的变化联系起来。蛋白质结构的整体特征沿压力仅有轻微改变。然而，Voronoi残基体积的值表明，α螺旋的残基比β折叠的残基压缩程度更大。在模拟中，α螺旋也表现出最大的内部流动性和变形。根据MD模拟快照计算得到的1H化学位移的非线性与实验观察到的化学位移的非线性在定性上是一致的。
