Institut für Immungenetik, Charité - Universitätsmedizin Berlin, Campus Benjamin Franklin, Freie Universität Berlin, Thielallee 73, 14195 Berlin, Germany.
Biophys Chem. 2012 Jun;167:26-35. doi: 10.1016/j.bpc.2012.04.001.
β(2)-microglobulin (β(2)m) is the smallest building block of molecules belonging to the immunoglobulin superfamily. By comparing thermodynamic and structural characteristics of chicken β(2)m with those of other species, we seek to elucidate whether it is possible to pinpoint features that set the avian protein apart from other β(2)m. The thermodynamic assays revealed that chicken β(2)m exhibits a lower melting temperature than human β(2)m, and the H/D exchange behavior observed by infrared spectroscopy indicates a more flexible structure of the former protein. To understand these differences at a molecular level, we determined the structure of free chicken β(2)m by X-ray crystallography to a resolution of 2.0 Å. Our comparisons indicate that certain biophysical characteristics of the chicken protein, particularly its conformational flexibility, diverge considerably from those of the other β(2)m analyzed, although basic structural features have been retained through evolution.
β(2)-微球蛋白（β(2)m）是免疫球蛋白超家族中最小的分子构建块。通过比较鸡β(2)m与其他物种的热力学和结构特征，我们试图阐明是否有可能确定使禽类蛋白质区别于其他β(2)m 的特征。热力学测定表明，鸡β(2)m 的熔点低于人β(2)m，红外光谱观察到的 H/D 交换行为表明前者的结构更具柔韧性。为了在分子水平上理解这些差异，我们通过 X 射线晶体学确定了游离鸡β(2)m 的结构，分辨率为 2.0 Å。我们的比较表明，尽管经过进化保留了基本的结构特征，但鸡蛋白的某些生物物理特性，特别是其构象灵活性，与其他分析的β(2)m 有很大的不同。
