title: Peptide aptamers: exchange of the thioredoxin-A scaffold by alternative platform proteins and its influence on target protein binding.
abstract: Peptide aptamers have emerged as powerful new tools for molecular medicine. They can specifically bind to and functionally inactivate a given target molecule under intracellular conditions. Typically, peptide aptamers are generated by screening a randomized peptide expression library, displayed from the Escherichia coli thioredoxin A (TrxA) protein. Here, we transferred peptide moieties from defined TrxA-based peptide aptamers to alternative scaffold proteins, such as the green fluorescent protein and staphylococcal nuclease. Yeast and mammalian two-hybrid assays as well as in vitro binding analyses show that the TrxA scaffold can be a major determinant for the binding of peptide aptamers. In addition, we demonstrate that TrxA can correctly display peptide sequences that correspond to the binding domains of natural interaction partners. Therefore, sequence analyses of TrxA-based peptide aptamers, isolated by two-hybrid screening from randomized expression libraries, should also be useful to find cellular binding partners for a given target protein, by homology.
authors.affiliation: Angewandte Tumorvirologie, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Klevenz
authors.forename: K
authors.initials: K
authors.lastname: Butz
authors.forename: F
authors.initials: F
authors.lastname: Hoppe-Seyler
mesh_terms: D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D009856:Oncogene Proteins, Viral / Q000378:metabolism; D010455:Peptides / Q000378:metabolism*; D011485:Protein Binding; D012097:Repressor Proteins; D013879:Thioredoxins / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: C068651:E6 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D010455:Peptides; D012097:Repressor Proteins; D013879:Thioredoxins