X-Ray Crystal Structure Analysis of Recombinant Interleukin-2 and beta-Interferon

1)由于重组DNA技术，某些淋巴因子和细胞因子，如白细胞介素-2 （IL-2）和β -干扰素（ifn - β）现在是可用的，样品的数量可用于晶体学研究。然而，从这种样品中得到的晶体往往是无序的、孪生的和脆性的。为了应对这些挫折，我们首先改进了x射线衍射数据采集方法，采用同步加速器束、成像板和改进软件。2)我们成功地生长了IL-2的六方、正交和单气候晶体。然而，即使是最好的单斜晶也表现出明显的抗辐射损伤能力。虽然我们能够证明Met 104的亚砜化是负责任的，但我们无法找到有效的补救措施。3)我们成功地生长了ifn - β的正交和六方晶体。六方晶体似乎是全尺寸结构分析的理想晶体。发现了三个有希望的重原子衍生物。寻找重原子结合位点的尝试正在进行中。我们希望在一年内得到ifn - β的三维结构。

1) Thanks to recombinant DNA technique, certain lymphokines and cytokines such as interleukin-2 (IL-2) and beta-Interferon (IFN-beta) are now available with the amount of sample feasible for crystallographic study. However the crystals obtained from such sample tend to be disordered, twinned and brittle. To cope with such setbacks, we first improved the method of X-ray diffraction data collection by employing synchrotron beam, imaging plate and by improving the softwares.2) We succeeded in growing hexagonal, orthorhombic and monoclimic crystals of IL-2. However even the best of these (the monoclinic crystal) showed marked weakness against radiation damage. Although we were able to show that sulfoxidation of Met 104 was responsible, we could not find effective remedy for this effect.3) We succeeded in growing orthorhombic and hexagonal crystals of IFN-beta. The hexagonal crystal seems almost ideal for full scale structure analysis. Three promising heavy-atom derivatives were found. Attempt at locating the heavy-atom binding sites are under way. We expect to get three-dimensional structure of IFN-beta within a year.