Marabotti Anna, Ausili Alessio, Staiano Maria, Scirè Andrea, Tanfani Fabio, Parracino Antonietta, Varriale Antonio, Rossi Mosè, D'Auria Sabato
Laboratorio di Bioinformatica, Istituto di Scienze dell'Alimentazione, CNR, Avellino, Italy.
Biochemistry. 2006 Oct 3;45(39):11885-94. doi: 10.1021/bi061158k.
The effect of the pressure on the structure and stability of the D-galactose/D-glucose binding protein from Escherichia coli in the absence (GGBP) and in the presence (GGBP/Glc) of glucose was studied by Fourier transform infrared (FT-IR) spectroscopy and molecular dynamic (MD) simulations. FT-IR spectroscopy experiments showed that the protein beta-structures are more resistant than alpha-helices structures to pressure value increases. In addition, the infrared data indicated that the binding of glucose stabilizes the protein structure against high pressure values, and the protein structure does not completely unfold up to pressure values close to 9000 bar. MD simulations allow a prediction of the most probable configuration of the protein, consistent with the increasing pressures on the two systems. The detailed analysis of the structures at molecular level confirms that, among secondary structures, alpha-helices are more sensitive than beta-structures to the destabilizing effect of high pressure and that glucose is able to preserve the structure of the protein in the complex. Moreover, the evidence of the different resistance of the two domains of this protein to high pressure is investigated and explained at a molecular level, indicating the importance of aromatic amino acid in protein stabilization.
通过傅里叶变换红外（FT-IR）光谱和分子动力学（MD）模拟，研究了压力对大肠杆菌D-半乳糖/D-葡萄糖结合蛋白在无葡萄糖（GGBP）和有葡萄糖（GGBP/Glc）存在时的结构和稳定性的影响。FT-IR光谱实验表明，蛋白质的β-结构比α-螺旋结构对压力值增加更具抗性。此外，红外数据表明，葡萄糖的结合使蛋白质结构在高压下更稳定，并且在压力值接近9000巴时蛋白质结构不会完全展开。MD模拟可以预测蛋白质最可能的构型，这与两个系统上不断增加的压力一致。在分子水平上对结构的详细分析证实，在二级结构中，α-螺旋比β-结构对高压的去稳定作用更敏感，并且葡萄糖能够在复合物中保持蛋白质的结构。此外，在分子水平上研究并解释了该蛋白质两个结构域对高压的不同抗性证据，表明芳香族氨基酸在蛋白质稳定中的重要性。
