Faculty of Life Sciences, University of Manchester, Manchester M13 9PL, UK.
J Synchrotron Radiat. 2011 Jan;18(1):79-83. doi: 10.1107/S0909049510034977. Epub 2010 Nov 5.
The low-resolution structure of α-crustacyanin has been determined to 30 Å resolution using negative-stain electron microscopy (EM) with single-particle averaging. The protein, which is an assembly of eight β-crustacyanin dimers, appears asymmetrical and rather open in layout. A model was built to the EM map using the X-ray crystallographic structure of β-crustacyanin guided by PISA interface analyses. The model has a theoretical sedimentation coefficient that matches well with the experimentally derived value from sedimentation velocity analytical ultracentrifugation. Additionally, the EM model has similarities to models calculated independently by rigid-body modelling to small-angle X-ray scattering (SAXS) data and extracted in silico from the β-crustacyanin crystal lattice. Theoretical X-ray scattering from each of these models is in reasonable agreement with the experimental SAXS data and together suggest an overall design for the α-crustacyanin assembly.
使用负染电子显微镜（EM）和单颗粒平均法，将 α-甲壳蓝蛋白的低分辨率结构解析至 30 Å 分辨率。该蛋白是由八个β-甲壳蓝蛋白二聚体组成的复合物，其结构在外观上呈现不对称且相对开放的特点。利用 PISA 界面分析，以 X 射线晶体学结构的β-甲壳蓝蛋白为指导，为 EM 图谱构建了一个模型。该模型的理论沉降系数与沉降速度分析超速离心实验得出的实验值吻合良好。此外，EM 模型与通过刚体建模计算的模型、从小角度 X 射线散射（SAXS）数据中提取的模型以及从β-甲壳蓝蛋白晶格中提取的模型具有相似性。这些模型的理论 X 射线散射与实验 SAXS 数据基本一致，共同为α-甲壳蓝蛋白组装体提供了一个整体设计。
