Abstract
Two different forms of crystals (potentially) suitable for x-ray structure analysis were obtained for recombinant human interleukin-2 (IL-2) using ammonium sulfate as a precipitant in the pH range of 6.3-7.3 (in the case of hexagonal bipyramidal crystals) and 4.5-5.5 (in the case of plate crystals). The hexagonal bipyramidal crystal belongs to a hexagonal space group P6(2)22 or P6(4)22 with a = b = 105.8 A and c = 122.2 A. The crystal diffracts up to 3.4 A resolution and contains 2 or 3 IL-2 molecules in an asymmetric unit. The plate crystal belongs to an orthorhombic space group P2(1)2(1)2 with a = 47.9 A, b = 79.6 A, and c = 31.9 A. The crystal diffracts up to 2.5 A resolution and contains only 1 IL-2 molecule in an asymmetric unit. These facts reconfirmed crystallographically the high homogeneity of the present preparation of human recombinant IL-2.
Highlights
The crystal diffracts up to 3.4 A resolution and contains 2 or 3 IL-2 molecules plate crystal belongsto
The expressed protein was dissolved and quantifor x-ray structure analysis were obtained for recom- tatively refolded intoa biologically active form througha binant human interleukin-2 (IL-2) using ammonium specific procedure devised recently [21]
The correctly resulfate as a precipitant in thepH range of 6.3-7.3 (in folded protein was purified to homogeneity by successive pt5hy.5erac(mainsiedthaoelfcchraeysxsetaagolofbnpeallaol tnbegipcsyrtyroastmaalihsd)ea.xlTcarhgyeosnhtaaelxlsa)sgpaonandcae4l g.b5ri-o-yppchrerloimmaintoagryraxp-hriaeys.sNtuodwieswoef report on the crystallization human recombinant IL-2
Summary
The crystal diffracts up to 3.4 A resolution and contains 2 or 3 IL-2 molecules plate crystal belongsto. Hanging drops of 10 pl each were equilibrated with reservoir solutions of1.0 ml each containing one precipitant such as ammonium sulfate, sodium chloride, sodium citby successive chromatographies [10,11,12,13]. Identification of Crystals as ZL-2 by RP-HPLC and Bioassay-The crystals that appeared in the droplets were collected and washed 3 times with the corresponding reservoir solutions to remove excess structure has been noted [15].
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