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PKU mutation p.G46S prevents the stereospecific binding of l‐phenylalanine to the dimer of human phenylalanine hydroxylase regulatory domain

Mammalian phenylalanine hydroxylase (PAH) has a potential allosteric regulatory binding site for l‐phenylalanine (l‐Phe), in addition to its catalytic site. This arrangement is supported by a crystal structure of a homodimeric truncated form of the regulatory domain of human PAH (hPAH‐RD (1–118/19–1...

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Detalles Bibliográficos
Autores principales: Leandro, João, Saraste, Jaakko, Leandro, Paula, Flatmark, Torgeir
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5292662/
https://www.ncbi.nlm.nih.gov/pubmed/28174686
http://dx.doi.org/10.1002/2211-5463.12175
Descripción
Sumario:Mammalian phenylalanine hydroxylase (PAH) has a potential allosteric regulatory binding site for l‐phenylalanine (l‐Phe), in addition to its catalytic site. This arrangement is supported by a crystal structure of a homodimeric truncated form of the regulatory domain of human PAH (hPAH‐RD (1–118/19–118)) [Patel D et al. (2016) Sci Rep doi: 10.1038/srep23748]. In this study, a fusion protein of the domain (MBP‐(pep(Xa))‐hPAH‐RD (1–120)) was overexpressed and recovered in a metastable and soluble state, which allowed the isolation of a dimeric and a monomeric fusion protein. When cleaved from MBP, hPAH‐RD forms aggregates which are stereospecifically inhibited by l‐Phe (> 95%) at low physiological concentrations. Aggregation of the cleaved dimer of the mutant form hPAH‐G46S‐RD was not inhibited by l‐Phe, which is compatible with structurally/conformationally changed βαββαβ ACT domain folds in the mutant.