PDBsum entry: 1mmk

Oxidoreductase

PDB id: 1mmk

Contents

Protein chain

309 a.a. *

Ligands

SO4

H4B

TIH

Metals

FE2

Waters ×182

* Residue conservation analysis

PDB id:

1mmk

Name:

Oxidoreductase

Title:

Crystal structure of ternary complex of the catalytic domain of human phenylalanine hydroxylase ((feii)) complexed with tetrahydrobiopterin and thienylalanine

Structure:

Phenylalanine-4-hydroxylase. Chain: a. Fragment: catalytic domain (residues 103-427). Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: pah. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.00Å R-factor: 0.199 R-free: 0.229

Authors:

O.A.Andersen,T.Flatmark,E.Hough

Key ref:

O.A.Andersen et al. (2003). 2.0A resolution crystal structures of the ternary complexes of human phenylalanine hydroxylase catalytic domain with tetrahydrobiopterin and 3-(2-thienyl)-L-alanine or L-norleucine: substrate specificity and molecular motions related to substrate binding. J Mol Biol, 333, 747-757. PubMed id: 14568534 DOI: 10.1016/j.jmb.2003.09.004

Date:

04-Sep-02 Release date: 04-Sep-03

Protein chain

P00439  (PH4H_HUMAN) -  Phenylalanine-4-hydroxylase

Seq: 452 a.a.

Struc: 309 a.a.

Enzyme reactions

• Enzyme class: E.C.1.14.16.1 - Phenylalanine 4-monooxygenase.
• Pathway: Phenylalanine and Tyrosine Biosynthesis
• Reaction: L-phenylalanine + tetrahydrobiopterin + O₂ = L-tyrosine + 4a-hydroxytetrahydrobiopterin

L-phenylalanine (Bound ligand (Het Group name = TIH) matches with 76.00% similarity) + tetrahydrobiopterin (Bound ligand (Het Group name = H4B) corresponds exactly) + O(2) = L-tyrosine + 4a-hydroxytetrahydrobiopterin

• Cofactor: Iron

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

 Gene Ontology (GO) functional annotation 

• Biological process: oxidation reduction (2 terms)
• Biochemical function: monooxygenase activity (3 terms)

reference

DOI no: 10.1016/j.jmb.2003.09.004

J Mol Biol 333:747-757 (2003)

PubMed id: 14568534

2.0A resolution crystal structures of the ternary complexes of human phenylalanine hydroxylase catalytic domain with tetrahydrobiopterin and 3-(2-thienyl)-L-alanine or L-norleucine: substrate specificity and molecular motions related to substrate binding.

O.A.Andersen, A.J.Stokka, T.Flatmark, E.Hough.

ABSTRACT

The crystal structures of the catalytic domain of human phenylalanine hydroxylase (hPheOH) in complex with the physiological cofactor 6(R)-L-erythro-5,6,7,8-tetrahydrobiopterin (BH(4)) and the substrate analogues 3-(2-thienyl)-L-alanine (THA) or L-norleucine (NLE) have been determined at 2.0A resolution. The ternary THA complex confirms a previous 2.5A structure, and the ternary NLE complex shows that similar large conformational changes occur on binding of NLE as those observed for THA. Both structures demonstrate that substrate binding triggers structural changes throughout the entire protomer, including the displacement of Tyr138 from a surface position to a buried position at the active site, with a maximum displacement of 20.7A for its hydroxyl group. Two hinge-bending regions, centred at Leu197 and Asn223, act in consort upon substrate binding to create further large structural changes for parts of the C terminus. Thus, THA/L-Phe binding to the active site is likely to represent the epicentre of the global conformational changes observed in the full-length tetrameric enzyme. The carboxyl and amino groups of THA and NLE are positioned identically in the two structures, supporting the conclusion that these groups are of key importance in substrate binding, thus explaining the broad non-physiological substrate specificity observed for artificially activated forms of the enzyme. However, the specific activity with NLE as the substrate was only about 5% of that with THA, which is explained by the different affinities of binding and different catalytic turnover.

Selected figure(s)

Figure 2.
Figure 2. A stereo view of the electron density at the active sites of (a) the hPheOH-Fe(II)·BH[4]·THA structure and (b) hPheOH-Fe(II)·BH[4]·NLE structure. Blue electron density from s[A]-weighted F[o] -F[c] maps is covered at 1.0s while green and red electron density is s[A]-weighted F[o] -F[c] maps covered at 3.0 and 4.0s, respectively, omitting water ligands. The Figure was produced using BOBSCRIPT[35.] and Raster3D. [36.]

Figure 7.
Figure 7. A view of the two hinge regions in the catalytic domain of hPheOH in (a) the crystal structure of the binary complex and (b) in the ternary complex with THA as the substrate. The centre of the hinge regions, i.e. Leu197 and Asp222-Asn223, are shown in ball-and-stick format. Side-chains beyond C^b are omitted for clarity. The axis of helix 181-201 is shown by a line. This Figure was prepared with MOLSCRIPT[37.] and Raster3D. [36.]

The above figures are reprinted by permission from Elsevier: J Mol Biol (2003, 333, 747-757) copyright 2003.

Figures were selected by an automated process.