Phenylalanine Binding Is Linked to Dimerization of the Regulatory Domain of Phenylalanine Hydroxylase
نویسندگان
چکیده
Analytical ultracentrifugation has been used to analyze the oligomeric structure of the isolated regulatory domain of phenylalanine hydroxylase. The protein exhibits a monomer-dimer equilibrium with a dissociation constant of ~46 μM; this value is unaffected by the removal of the 24 N-terminal residues or by phosphorylation of Ser16. In contrast, phenylalanine binding (Kd = 8 μM) stabilizes the dimer. These results suggest that dimerization of the regulatory domain of phenylalanine hydroxylase is linked to allosteric activation of the enzyme.
منابع مشابه
The Amino Acid Specificity for Activation of Phenylalanine Hydroxylase Matches the Specificity for Stabilization of Regulatory Domain Dimers
Liver phenylalanine hydroxylase is allosterically activated by phenylalanine. The structural changes that accompany activation have not been identified, but recent studies of the effects of phenylalanine on the isolated regulatory domain of the enzyme support a model in which phenylalanine binding promotes regulatory domain dimerization. Such a model predicts that compounds that stabilize the r...
متن کاملReport of VNTR with 13 Repeats Linked to Phenylalanine Hydroxylase Locus in Unaffected Members of Two PKU Families
Phenylketonuria (PKU) is one of the most common metabolic inborn diseases caused by mutations in the phenylalanine hydroxylase (PAH) gene. This gene is linked to a variable number of tandem repeats (VNTR) region which is a polymorphic marker that facilitates the implementation of prenatal diagnosis and carrier screening. In this study, VNTR with 13 repeats that has not been reported previously ...
متن کاملStructural basis for ligand-dependent dimerization of phenylalanine hydroxylase regulatory domain.
The multi-domain enzyme phenylalanine hydroxylase (PAH) catalyzes the hydroxylation of dietary I-phenylalanine (Phe) to I-tyrosine. Inherited mutations that result in PAH enzyme deficiency are the genetic cause of the autosomal recessive disorder phenylketonuria. Phe is the substrate for the PAH active site, but also an allosteric ligand that increases enzyme activity. Phe has been proposed to ...
متن کاملActivation of Phenylalanine Hydroxylase by Phenylalanine Does Not Require Binding in the Active Site
Phenylalanine hydroxylase (PheH), a liver enzyme that catalyzes the hydroxylation of excess phenylalanine in the diet to tyrosine, is activated by phenylalanine. The lack of activity at low levels of phenylalanine has been attributed to the N-terminus of the protein's regulatory domain acting as an inhibitory peptide by blocking substrate access to the active site. The location of the site at w...
متن کاملMutation analysis of Phenylalanine hydroxylase gene in Iranian patients with Phenylketonuria
Background: Phenylketonuria as the most common genetic metabolic disorder is the result of disruption of the phenylalanine hydroxylase gene. This study was carried out to explore the phenylalanine hydroxylase gene mutation status of Iranian phenylketonuria patients. Methods: Blood samples were collected from 30 patients, and hot spot areas of the phenylalanine hydroxylase gene, in...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره 53 شماره
صفحات -
تاریخ انتشار 2014