MONOCLONAL-ANTIBODY, A NOVEL PROBE FOR PROTEIN-FOLDING

Two monoclonal antibodies (McAb2C9, McAb1E5) against Staphylococcal nu clease R (SNase R) and its N-terminal peptide fragments were prepared, purified and characterized. Further studies show that the intact enzy me SNase R and its seven N-terminal peptide fragments:differ in their interaction with McAb2C9. SNase R, SNR121, SNR102, SNR79 and SNR52 can bind to McAb2C9 readily, while fragments of SNR141, SNR135, SNR110 re act with the antibody poorly. If this difference is due to diverse ext ent of exposure of the specific epitope in the fragments, it is sugges ted that the conformation of the peptide is subjected to continuous ad justments through chain elongation until the biologically active prote in is formed. This result supports Tsou's hypothesis of nascent peptid e folding experimentally.