6hyc

The structure of full-length human phenylalanine hydroxylase in complex with the cofactor and negative regulator tetrahydrobiopterin

spinqualitylabelsall models 6hyc, resolution 3.18Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6hyc is a 4 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.18Å Ligands: H4B Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Disease PH4H_HUMAN Defects in PAH are the cause of phenylketonuria (PKU) [MIM:261600. PKU is an autosomal recessive inborn error of phenylalanine metabolism, due to severe phenylalanine hydroxylase deficiency. It is characterized by blood concentrations of phenylalanine persistently above 1200 mumol (normal concentration 100 mumol) which usually causes mental retardation (unless low phenylalanine diet is introduced early in life). They tend to have light pigmentation, rashes similar to eczema, epilepsy, extreme hyperactivity, psychotic states and an unpleasant 'mousy' odor. Defects in PAH are the cause of non-phenylketonuria hyperphenylalaninemia (Non-PKU HPA) [MIM:261600. Non-PKU HPA is a mild form of phenylalanine hydroxylase deficiency characterized by phenylalanine levels persistently below 600 mumol, which allows normal intellectual and behavioral development without treatment. Non-PKU HPA is usually caused by the combined effect of a mild hyperphenylalaninemia mutation and a severe one. Defects in PAH are the cause of hyperphenylalaninemia (HPA) [MIM:261600. HPA is the mildest form of phenylalanine hydroxylase deficiency. Function PH4H_HUMAN Publication Abstract from PubMed Phenylalanine hydroxylase (PAH) is a key enzyme in the catabolism of phenylalanine, and mutations in this enzyme cause phenylketonuria (PKU), a genetic disorder that leads to brain damage and mental retardation if untreated. Some patients benefit from supplementation with a synthetic formulation of the cofactor tetrahydrobiopterin (BH4) that partly acts as a pharmacological chaperone. Here we present structures of full-length human PAH (hPAH) both unbound and complexed with BH4 in the precatalytic state. Crystal structures, solved at 3.18-A resolution, show the interactions between the cofactor and PAH, explaining the negative regulation exerted by BH4 BH4 forms several H-bonds with the N-terminal autoregulatory tail but is far from the catalytic Fe(II) Upon BH4 binding a polar and salt-bridge interaction network links the three PAH domains, explaining the stability conferred by BH4 Importantly, BH4 binding modulates the interaction between subunits, providing information about PAH allostery. Moreover, we also show that the cryo-EM structure of hPAH in absence of BH4 reveals a highly dynamic conformation for the tetramers. Structural analyses of the hPAH:BH4 subunits revealed that the substrate-induced movement of Tyr138 into the active site could be coupled to the displacement of BH4 from the precatalytic toward the active conformation, a molecular mechanism that was supported by site-directed mutagenesis and targeted molecular dynamics simulations. Finally, comparison of the rat and human PAH structures show that hPAH is more dynamic, which is related to amino acid substitutions that enhance the flexibility of hPAH and may increase the susceptibility to PKU-associated mutations. Structure of full-length human phenylalanine hydroxylase in complex with tetrahydrobiopterin.,Flydal MI, Alcorlo-Pages M, Johannessen FG, Martinez-Caballero S, Skjaerven L, Fernandez-Leiro R, Martinez A, Hermoso JA Proc Natl Acad Sci U S A. 2019 May 22. pii: 1902639116. doi:, 10.1073/pnas.1902639116. PMID:31118288 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Hydroxylases 3D structures

Proteopedia Page Contributors and Editors (what is this?)

OCA