A peptide with binding properties for tumor necrosis factor (TNFα) sequence 144-157 has been designed, using a computer-assisted method able to create peptide sequences hydropathically complementary to a given sequence. The complementary peptide was synthesized in a multimeric form starting from an octadentate polylysine core, to facilitate its immobilization and to provide interaction multivalency. Once immobilized on a solid support to prepare an affinity column, it recognized the target TNF144-157 peptide selectively from crude peptide mixtures containing TNF fragments encompassing the entire TNFα sequence. Similar selectivity and specificity were shown for full-length recombinant TNFα, allowing its purification from crude Escherichia coli extracts. The octameric complementary peptide preserved its recognition properties for TNFα and biotinylated TNFa even after coating on microtiter plates. Competitive binding occurred with unlabeled TNFα in the range between 0.01 and 10 μg/ml, in the presence of detergent such as 0.05% Tween 20 and in the presence of 1% normal goat serum. The effect of complementary peptide multimerization was evidenced by its enhanced binding affinity for TNFα, which exists in solution as a trimer, while the target TNF[144-157] peptide was recognized with much lower strength. The dissociation constant for interaction with TNFα was close to 10 nm, allowing its easy detection by solid phase assays in concentrations as low as 10 pmol/ml.
ASJC Scopus subject areas
- Molecular Biology