Subunit interaction in the CCAAT-binding heteromeric complex is mediated by a very short alpha-helix in HAP2

• Published in: Proceedings of the National Academy of Sciences - PNAS 1994-04, Vol.91 (8), p.3009-3013
• Main Authors: Xing, Y.Y, Zhang, S.G, Olesen, J.T, Rich, A, Guarente, L
• Format: Article
• Language: English
• Subjects: ADN; Amino Acid Sequence; Amino acids; Biochemistry; Biological and medical sciences; CCAAT-Binding Factor; Circular Dichroism; DNA; Fundamental and applied biological sciences. Psychology; Fungal Proteins - chemistry; Fungal Proteins - metabolism; Gels; Genetic mutation; Lactates; Leucine Zippers; Macromolecular Substances; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Molecules; MUTACION INDUCIDA; Mutagenesis; Mutagenesis, Site-Directed; MUTANT; MUTANTES; MUTATION PROVOQUEE; Protein Binding; Protein Structure, Secondary; PROTEINAS; PROTEINE; Proteins; SACCHAROMYCES CEREVISIAE; Saccharomyces cerevisiae - chemistry; Structure-Activity Relationship; Transcription Factors - chemistry; Transcription Factors - metabolism; Transcription. Transcription factor. Splicing. Rna processing; Yeasts
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.91.8.3009

We dissected the domain of HAP2 that mediates subunit association in the heteromeric CCAAT-binding complex, first by genetic mutational analysis and then by structural studies. The mutational data suggest that a very short region in HAP2 mediates protein-protein association and that the structure of this domain is likely to be an alpha-helix. The CD analyses of a 15-residue synthetic oligopeptide covering this region confirm this surmise. The oligopeptide indeed formed an unusually thermal stable alpha-helix in aqueous solution. Eight amino acids that lie along one face of this helix, including three arginines, are found to be critical for protein-protein association. The partner that interacts with this helical motif is likely to be another subunit in the HAP complex, since the CCAAT-binding factor is shown to contain one molecule of HAP2. Our results suggest that very short regions in proteins can encode precise structures and mediate stable and specific protein-protein recognition and interactions