Previous models of protein p36 based on proteolytic fragments describe the tail and core as 2 noninteracting domains. However, monoclonal antibody H28 recognized a discontinuous epitope, which covers the peptide segments around serine-25 in the tail and around glutamate-65 in the core of porcine p36. Thus, the phosphorylatable tyrosine-23 is much closer to the 1st consensus sequence (residues 46-62) of Ca2+/lipid-binding proteins than previously thought. This apposition is in line with biochem. expts. indicating an influence of core ligands on tyrosine phosphorylation and an enhanced Ca2+ requirement of the modified p36 in phospholipid binding. [on SciFinder (R)]