Harding M W, Handschumacher R E, Speicher D W
J Biol Chem. 1986 Jun 25;261(18):8547-55.
Cyclophilin, a specific cyclosporin A-binding protein has been purified to homogeneity from human spleen and bovine thymus cytosol. Purification of bovine and human cyclophilin was achieved by large scale molecular filtrations, Matrex Blue A affinity chromatography, preparative isoelectric focusing, phenyl-Sepharose chromatography, and weak cation exchange high performance liquid chromatography. Major and minor bovine and human cyclophilin isoforms were identified and found to have an apparent molecular weight of 17,000 and very similar amino acid compositions. The complete amino acid sequence of the major bovine cyclophilin isoform (163 residues, Mr 17,737) was determined from analysis of peptides derived by endoproteinase lysine C and cyanogen bromide cleavage and an NH2-terminal sequence of the intact protein. The first 72 NH2-terminal residues of the major human cyclophilin isoform were also determined and found to be identical to bovine cyclophilin. A computer search of cyclophilin with the National Biomedical Research Foundation database (3,182 protein sequences) did not detect any significant homologies. Cyclophilin represents a new class of abundant, highly conserved cytosolic proteins that probably play an important role in the regulation of T lymphocyte activation and proliferation.
亲环蛋白，一种特定的环孢菌素A结合蛋白，已从人脾脏和牛胸腺胞质溶胶中纯化至同质。通过大规模分子过滤、Matrex Blue A亲和色谱、制备性等电聚焦、苯基琼脂糖色谱和弱阳离子交换高效液相色谱实现了牛和人亲环蛋白的纯化。鉴定出了主要和次要的牛和人亲环蛋白同工型，发现其表观分子量为17,000，氨基酸组成非常相似。通过对内肽酶赖氨酸C和溴化氰裂解产生的肽段以及完整蛋白的NH2末端序列进行分析，确定了主要牛亲环蛋白同工型（163个残基，Mr 17,737）的完整氨基酸序列。还确定了主要人亲环蛋白同工型的前72个NH2末端残基，发现其与牛亲环蛋白相同。使用国家生物医学研究基金会数据库（3,182个蛋白质序列）对亲环蛋白进行计算机搜索未发现任何显著同源性。亲环蛋白代表了一类新的丰富、高度保守的胞质蛋白，可能在T淋巴细胞活化和增殖的调节中起重要作用。
