Analysis of gp39/CD40 Interactions Using Molecular Models and Site-Directed Mutagenesis
| Autor: | Siadak Anthony W, A Aruffo, Randolph J. Noelle, Diane Hollenbaugh, Gordon Marcia L, Jürgen Bajorath, N J Chalupny, T L Spoon, John Marken |
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| Rok vydání: | 1995 |
| Předmět: |
Models
Molecular Molecular model Stereochemistry T-Lymphocytes CD40 Ligand Molecular Sequence Data Plasma protein binding Ligands Biochemistry Receptors Tumor Necrosis Factor Antigens CD Humans Amino Acid Sequence CD40 Antigens Binding site Site-directed mutagenesis Saturated mutagenesis Lymphotoxin-alpha Peptide sequence Cells Cultured chemistry.chemical_classification B-Lymphocytes Binding Sites Membrane Glycoproteins Sequence Homology Amino Acid Chemistry Mutagenesis hemic and immune systems Flow Cytometry Amino acid Antigens Differentiation B-Lymphocyte Mutagenesis Site-Directed Protein Binding |
| Zdroj: | Biochemistry. 34:9884-9892 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi00031a009 |
| Popis: | The interaction between gp39 (CD40L, TRAP, T-BAM) on activated T cells and mast cells and CD40 on antigen-presenting cells modulates immune responses. Gp39 and CD40 are homologous to tumor necrosis factor (TNF) and its receptor (TNFR), respectively. The TNF-beta/TNFR interaction has been analyzed on the basis of mutagenesis experiments and crystal structures. Using the interaction of TNF-beta/TNFR as a guide, we previously reported a site-directed mutagenesis study in which we identified residues in gp39 (K143, Y145) and CD40 (Y82, D84, N86) involved in gp39/CD40 interactions. Here we describe the use of the TNF-beta/TNFR complex crystal structure as a template to prepare molecular models of gp39, CD40, and their approximate interaction. The application of these models has allowed us to extend our mutagenesis analysis of gp39/CD40 interactions. These experiments have led to the identification of additional gp39 (Y146, R203, Q220) and CD40 (E74, E117) residues that contribute to the gp39/CD40 interaction. We also further explored the importance of gp39 residue Y145 and CD40 residue Y82 for the gp39/CD40 interaction by conservatively replacing these residues with Phe. The results of these studies have enabled us to approximately outline the binding sites in gp39 and CD40. It appears that the gp39/CD40 interaction is centered on at least two clusters of residues and involves residues of two adjacent gp39 monomers. The molecular regions involved in the gp39/CD40 interaction essentially correspond to those in the homologous TNF-beta/TNFR system. |
| Databáze: | OpenAIRE |
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