A monoclonal antibody against a lectin-like substance (LS) of Eikenella corrodens (Ec) was used for screening the Ec DNA library. Three positive clones that carried an identical 12-kb segment were obtained. A 25-kDa protein, which specifically binds to the antibody, was overproduced in all of the Escherichia coli clones. Deletion analysis showed that the gene encoding the 25-kDa protein was located within a 1.2-kb segment. The nucleotide (nt) sequence of this segment contained an open reading frame encoding a protein of 24600 Da. We purified the 25-kDa protein from the cloned E. coli strain. The sequence of the first 10 amino acids(aa) from the N-terminus of the purified 25-kDa protein agreed with that deduced from the nt sequence. Since the monoclonal antibody used in this study inhibits the physiological activity of EcLS, we concluded that the 25-kDa protein is a component of the adhesin complex, which is located near the carbohydrate recognition domain of lectin in EcLS.