Sanchez-Ruiz J M, Martinez-Carrion M
School of Basic Life Sciences, Division of Molecular Biology and Biochemistry, University of Missouri, Kansas City 64110.
Biochemistry. 1988 May 3;27(9):3338-42. doi: 10.1021/bi00409a033.
A Fourier-transform infrared spectroscopic study of hen egg phosvitin and ovalbumin has been carried out. Bands arising from monoanionic and dianionic phosphate monoester [Shimanouchi, T., Tsuboi, M., & Kyogoku, Y. (1964) Adv. Chem. Phys. 8, 435-498] can be identified easily in the 1300-930 cm-1 region in spectra of solutions of O-phosphoserine and phosvitin, a highly phosphorylated protein. On the other hand, spectra of ovalbumin show a relatively strong absorption above 1000 cm-1 arising from the protein moiety. Below 1000 cm-1, a single band at 979 cm-1 is observed; this band is not present in spectra of dephosphorylated ovalbumin, and therefore, it has been assigned to the symmetric stretching of the phosphorylated Ser-68 and Ser-344 in the dianionic ionization state. In addition, bands arising from symmetric and antisymmetric stretchings of the monoanionic ionization state, and from the antisymmetric stretching of the dianionic state, can be detected above 1000 cm-1 in difference spectra of ovalbumin minus dephosphorylated ovalbumin. The effect of pH on the infrared spectra of O-phosphoserine, phosvitin, and ovalbumin is consistent with the phosphoserine residues undergoing ionization with pK values about 6. This study demonstrates that Fourier-transform infrared spectroscopy can be a useful technique to assess the ionization state of phosphoserine residues in proteins in solution.
已对鸡蛋中的卵黄高磷蛋白和卵清蛋白进行了傅里叶变换红外光谱研究。在O-磷酸丝氨酸和卵黄高磷蛋白（一种高度磷酸化的蛋白质）溶液的光谱中，1300 - 930 cm⁻¹区域内可轻松识别出由单阴离子和双阴离子磷酸单酯产生的谱带[岛野内，T.，津部，M.， & 京极，Y.（1964年）《化学物理进展》8，435 - 498]。另一方面，卵清蛋白的光谱在1000 cm⁻¹以上显示出相对较强的源于蛋白质部分的吸收。在1000 cm⁻¹以下，观察到一条位于979 cm⁻¹的谱带；该谱带在去磷酸化卵清蛋白的光谱中不存在，因此，它被归属于处于双阴离子电离状态的磷酸化丝氨酸-68和丝氨酸-344的对称伸缩振动。此外，在卵清蛋白减去去磷酸化卵清蛋白的差示光谱中，可在1000 cm⁻¹以上检测到源于单阴离子电离状态的对称和反对称伸缩振动以及双阴离子状态的反对称伸缩振动的谱带。pH对O-磷酸丝氨酸、卵黄高磷蛋白和卵清蛋白红外光谱的影响与磷酸丝氨酸残基以约6的pK值进行电离相一致。这项研究表明，傅里叶变换红外光谱可成为评估溶液中蛋白质中磷酸丝氨酸残基电离状态的有用技术。
