Backer Marina V, Gaynutdinov Timur I, Aloise Renee, Przekop Kristen, Backer Joseph M
SibTech Inc., 705 North Mountain Road, Newington, CT 06111, USA.
Protein Expr Purif. 2002 Dec;26(3):455-61. doi: 10.1016/s1046-5928(02)00546-6.
High affinity interaction between S-protein and S-peptide fragments of bovine pancreatic RNase A has been recently used for construction of molecular vehicles for targeted drug delivery. The vehicle is assembled as a complex of drug carrier conjugated S-protein with S-peptide-tagged targeting protein. To avoid random chemical crosslinking of drug carriers to S-protein, we constructed a mutant 16-124aa fragment of RNase A in which 122ala is replaced with a cysteine residue. The mutant and the corresponding wild type fragments expressed in Escherichia coli are refolded into functional conformations only in the presence of S-peptide. After the removal of S-peptide, both fragments retain the ability to bind S-peptide and S-peptide-tagged proteins. The 122cys residue in the mutant fragment is available for site-specific conjugation.
牛胰核糖核酸酶A的S蛋白与S肽片段之间的高亲和力相互作用最近被用于构建靶向药物递送的分子载体。该载体组装成药物载体共轭S蛋白与S肽标记靶向蛋白的复合物。为避免药物载体与S蛋白的随机化学交联，我们构建了核糖核酸酶A的突变体16 - 124aa片段，其中122ala被半胱氨酸残基取代。在大肠杆菌中表达的突变体和相应的野生型片段仅在S肽存在的情况下重折叠成功能构象。去除S肽后，两个片段都保留了结合S肽和S肽标记蛋白的能力。突变体片段中的122cys残基可用于位点特异性共轭。
