EFFECT OF PEPTIDE ACETYLATION ON ITS INTERACTION WITH ANTIPEPTIDE ANTIBODY

The effects of trace acetylation on the contact sites in peptide-antib ody binding have been investigated by using a label selection method. A 13-residue synthetic peptide having three lysines (LKLVEQQNPKVKL) co rresponding to sequence position 155-168 of beta 1,4-galactosyltransfe rase was used in this study. The four amino groups located throughout the peptide sequence, labeled appropriately, served as probing marker groups. The amino terminus region of the peptide was highly reactive t o trace acetylation. Over 80% of the label appeared in the amino termi nus region, most likely in the cw-amino group due to its lower pK valu e. Interestingly, acetylation of Lys10 and Lys12 (carboxy terminal reg ion) showed a selection for interacting with the antibody. This approa ch, using label selection affords high sensitivity and could be applic able for mapping antigen-antibody interaction site/s. (C) 1994 Academi c Press, Inc.