Bottomley M J, Robinson R C, Driscoll P C, Harlos K, Stuart D I, Aplin R T, Clements J M, Jones E Y, Dudgeon T J
Department of Biochemistry, University of Oxford, U.K.
J Mol Biol. 1994 Dec 9;244(4):464-8. doi: 10.1006/jmbi.1994.1743.
Soluble fragments of the extracellular region of vascular cell adhesion molecule 1 (VCAM-1) expressed in Escherichia coli retain functional adhesive activity. An integrin (VLA-4) binding fragment consisting of the N-terminal two immunoglobulin-like domains (VCAM-d1,2) has been crystallized. The crystals belong to space group P2(1)2(1)2(1) with cell dimensions of a = 52.7 A, b = 66.5 A, c = 113.2 A and contain two molecules in the crystallographic asymmetric unit. A batch of protein produced in the standard E. coli strain (HW1110), but grown in the presence of selenomethionine enriched media, showed 85% incorporation of selenium in place of sulphur at methionine residues. The selenomethionyl VCAM-d1,2 was crystallized by microseeding techniques initially using the native crystals for nucleation. Both native and selenomethionyl crystals diffract X-rays to a minimum Bragg spacing of 1.8 A.
在大肠杆菌中表达的血管细胞黏附分子1（VCAM-1）细胞外区域的可溶性片段保留了功能性黏附活性。由N端两个免疫球蛋白样结构域组成的整合素（VLA-4）结合片段（VCAM-d1,2）已结晶。晶体属于空间群P2(1)2(1)2(1)，晶胞参数为a = 52.7 Å，b = 66.5 Å，c = 113.2 Å，在晶体学不对称单元中含有两个分子。一批在标准大肠杆菌菌株（HW1110）中产生，但在富含硒代甲硫氨酸的培养基中生长的蛋白质，在甲硫氨酸残基处显示85%的硒取代了硫。最初使用天然晶体进行成核，通过微量接种技术使硒代甲硫酰基VCAM-d1,2结晶。天然晶体和硒代甲硫酰基晶体都能将X射线衍射到最小布拉格间距为1.8 Å。
