This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Valdez, B. C. Articles by Busch, H. Search for Related Content PubMed PubMed Citation Articles by Valdez, B. C. Articles by Busch, H.

Identification of an Epitope Region of the Human Proliferation-associated Nucleolar Antigen P120¹

Department of Pharmacology, Baylor College of Medicine, Houston, Texas 77030

An epitope region, located at amino acid residues 173–180 (EAAA-GIQW), of a human cell proliferation-associated nucleolar antigen, P120, has been defined by mutational analysis and competition assays. A synthetic peptide corresponding to this epitope region completely blocks the binding of the anti-P120 antibody to Escherichia coli-expressed P120 and the HeLa nucleolar P120 protein. Adjacent peptides lack inhibitory effects. The antigenic site includes a hydrophilic residue and a hydrophobic stretch. The glutamyl and tryptophanyl residues in this region make major contributions to the binding of P120 to its antibody, since peptides lacking either the glutamyl or the tryptophanyl residue do not block the antibody binding to the P120 antigen. This study provides a basis for drug design for specific binding to the epitope region of the P120 protein.

¹ This investigation was supported by the Cancer Research Center Grant CA-10893, awarded by the National Cancer Institute, Department of Health and Human Services, USPHS; The DeBakey Medical Foundation; The Davidson Fund; The Pauline Sterne Wolff Memorial Foundation; H. Leland Kaplan Cancer Research Endowment; Linda and Ronny Finger Cancer Research Endowment Fund; and The William S. Farish Fund.

² To whom requests for reprints should be addressed.

Received 10/27/89. Revised 1/ 8/90.