RESUMO
Polyglutamine tract-binding protein 1 (PQBP1) is an intrinsically disordered protein composed of a small folded WW domain and a long disordered region. PQBP1 binds to spliceosomal proteins WBP11 and U5-15kD through its N-terminal WW domain and C-terminal region, respectively. Here, we reveal that the binding between PQBP1 and WBP11 reduces the binding affinity between PQBP1 and U5-15kD. Our results suggest that the interaction between PQBP1 and WBP11 negatively modulates the U5-15kD binding of PQBP1 by an allosteric mechanism.
Assuntos
Proteínas de Transporte/química , Proteínas Nucleares/química , Ribonucleoproteína Nuclear Pequena U5/química , Regulação Alostérica/fisiologia , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Humanos , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Ligação Proteica/fisiologia , Domínios Proteicos , Fatores de Processamento de RNA , Ribonucleoproteína Nuclear Pequena U5/genética , Ribonucleoproteína Nuclear Pequena U5/metabolismoRESUMO
Polyglutamine tract-binding protein 1 (PQBP1) is an intrinsically disordered protein abundantly expressed in the brain. Mutations in the PQBP1 gene are causative for X-linked mental retardation disorders. Here, we investigated the structure of the C-terminal segment within the context of full-length PQBP1. We produced a segmentally isotope-labeled PQBP1 composed of a non-labeled segment (residues 1-219; N-segment) and a (13)C/(15)N-labeled segment (residues 220-265; C-segment). Our results demonstrate that the segmental isotope-labeling combined with NMR spectroscopy is useful for detecting a very weak intra-molecular interaction in an intrinsically disordered protein.
