Haelewyn J, Michiels L, Verhaert P, Hoylaerts M F, Witters R, De Ley M
Laboratory for Biochemistry, Katholieke Universiteit Leuven (KULeuven), Celestijnenlaan 200 G, B-3001 Leuven-Heverlee, Belgium.
Biochem J. 1997 Jun 1;324 ( Pt 2)(Pt 2):591-5. doi: 10.1042/bj3240591.
Recombinant human interferon gamma (IFN-gamma), produced in Escherichia coli, was selectively truncated at its C-terminus with chymotrypsin, clostripain or plasmin. The C-terminal amino acid residues of the three truncated IFN-gamma variants were identified as Phe136, Arg129 and Lys128, indicating the removal of 7, 14 and 15 amino acid residues from the full-length molecule. The absence of seven C-terminal residues did not influence the binding of IFN-gamma to its receptor. In contrast, the truncation of 14 residues resulted in a decrease in the Ka value to 1/24, as determined by surface plasmon resonance analysis. The removal of one additional amino acid residue from the C-terminal region of IFN-gamma led to a marked loss of receptor-binding capacity and biological activity. These observations demonstrate that Arg129 is an essential part of a functionally important C-terminal IFN-gamma sequence that is involved in receptor interaction.
在大肠杆菌中产生的重组人干扰素γ（IFN-γ），用胰凝乳蛋白酶、梭菌蛋白酶或纤溶酶在其C末端进行选择性截短。三种截短的IFN-γ变体的C末端氨基酸残基被鉴定为苯丙氨酸136、精氨酸129和赖氨酸128，这表明从全长分子中去除了7、14和15个氨基酸残基。缺少七个C末端残基并不影响IFN-γ与其受体的结合。相比之下，通过表面等离子体共振分析确定，截短14个残基导致Ka值降至1/24。从IFN-γ的C末端区域再去除一个氨基酸残基会导致受体结合能力和生物活性显著丧失。这些观察结果表明，精氨酸129是参与受体相互作用的功能性重要C末端IFN-γ序列的重要组成部分。
