Crystal structure of phenylalanine hydroxylase A313T mutant with 7,8-dihydrobiopterin bound

Experimental Data Snapshot

  • Resolution: 2.20 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.213 
  • R-Value Observed: 0.213 

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Correction of kinetic and stability defects by tetrahydrobiopterin in phenylketonuria patients with certain phenylalanine hydroxylase mutations.

Erlandsen, H.Pey, A.L.Gamez, A.Perez, B.Desviat, L.R.Aguado, C.Koch, R.Surendran, S.Tyring, S.Matalon, R.Scriver, C.R.Ugarte, M.Martinez, A.Stevens, R.C.

(2004) Proc Natl Acad Sci U S A 101: 16903-16908

  • DOI: https://doi.org/10.1073/pnas.0407256101
  • Primary Citation of Related Structures:  
    1TDW, 1TG2

  • PubMed Abstract: 

    Phenylketonuria patients harboring a subset of phenylalanine hydroxylase (PAH) mutations have recently shown normalization of blood phenylalanine levels upon oral administration of the PAH cofactor tetrahydrobiopterin [(6R)-L-erythro-5,6,7,8-tetrahydrobiopterin (BH4)]. Several hypotheses have been put forward to explain BH4 responsiveness, but the molecular basis for the corrective effect(s) of BH4 has not been understood. We have investigated the biochemical, kinetic, and structural changes associated with BH4-responsive mutations (F39L, I65T, R68S, H170D, E178G, V190A, R261Q, A300S, L308F, A313T, A373T, V388M, E390G, P407S, and Y414C). The biochemical and kinetic characterization of the 15 mutants studied points toward a multifactorial basis for the BH4 responsiveness; the mutants show residual activity (>30% of WT) and display various kinetic defects, including increased Km (BH4) and reduced cooperativity of substrate binding, but no decoupling of cofactor (BH4) oxidation. For some, BH4 seems to function through stabilization and protection of the enzyme from inactivation and proteolytic degradation. In the crystal structures of a phenylketonuria mutant, A313T, minor changes were seen when compared with the WT PAH structures, consistent with the mild effects the mutant has upon activity of the enzyme both in vitro and in vivo. Truncations made in the A313T mutant PAH form revealed that the N and C termini of the enzyme influence active site binding. Of fundamental importance is the observation that BH4 appears to increase Phe catabolism if at least one of the two heterozygous mutations has any residual activity remaining.

  • Organizational Affiliation

    Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Phenylalanine-4-hydroxylase308Homo sapiensMutation(s): 1 
Gene Names: PAH
UniProt & NIH Common Fund Data Resources
Find proteins for P00439 (Homo sapiens)
Explore P00439 
Go to UniProtKB:  P00439
PHAROS:  P00439
GTEx:  ENSG00000171759 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00439
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on H2B

Download Ideal Coordinates CCD File 
C9 H13 N5 O3
Query on FE

Download Ideal Coordinates CCD File 
B [auth A]FE (III) ION
Experimental Data & Validation

Experimental Data

  • Resolution: 2.20 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.213 
  • R-Value Observed: 0.213 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 66.534α = 90
b = 107.755β = 90
c = 124.282γ = 90
Software Package:
Software NamePurpose
d*TREKdata reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Revision History  (Full details and data files)

  • Version 1.0: 2004-11-30
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-10-27
    Changes: Database references, Derived calculations
  • Version 1.4: 2023-08-23
    Changes: Data collection, Refinement description