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根据人白细胞介素－２（ＩＬ－２）ａ螺旋Ｂ中氨基酸残基的空间分布选择性地突变了一些氨基酸残基，结果发现．５７Ｇｌｎ→Ｇｌｎ，６２Ｇｌｎ→Ｌｅｕ，６２Ｇｌｎ→Ａｒｇ和６５Ｐｒｏ→Ａｒｇ这些替换均使ＩＬ－２活性显著降低或丧失，而６３Ｌｅｕ→Ｓｅｒ或６４Ｌｙｓ→Ａｌａ对ＩＬ－２活性影响不大。从受体竞争抑制结合实验结果可知，上述不表现活性的突变体也同时丧失了与高亲和力受体的结合能力，这说明α螺旋Ｂ中这些位点对ＩＬ－２与受体结合有贡献，事实上，那些直接与受体β、γ亚基结合的残基所在螺旋为Ａ、Ｄ螺旋而非α螺旋Ｂ，由此我们认为α螺旋Ｂ虽不直接参与与受体β、γ亚基结合，但它在空间结构上对ＩＬ－２与受体β、γ亚基的结合产生了有利的影响，而５７Ｇｌｎ、６２Ｇｌｎ、６５Ｐｒｏ等残基则在此过程中发挥重要作用。
Based on the spatial distribution of amino acid residues in human interleukin-2 (IL-2) a-helix B, several amino acid residues were selectively mutated and found. The substitutions of 57Gln → Gln, 62Gln → Leu, 62Gln → Arg and 65Pro → Arg all significantly decreased or abolished the activity of IL-2, whereas 63Leu → Ser or 64Lys → Ala had little effect on IL-2 activity. From the results of the competitive inhibition of the binding assay, it is clear that the above-mentioned inactive mutants also lose their ability to bind to the high-affinity receptor, indicating that these sites in α-helix B contribute to the binding of IL-2 to the receptor, In fact, the helix of the residues directly bound to the receptor?,? Subunits is A, D helix instead of? Helix B, so we think that α helix B is not directly involved in binding to the receptor β, γ subunit , But it has a beneficial effect on the binding of IL-2 to receptor β and γ subunits in the spatial structure. However, residues such as 57Gln, 62Gln and 65Pro play an important role in this process.