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

被引:148
作者
Erlandsen, H
Pey, AL
Gámez, A
Pérez, B
Desviat, LR
Aguado, C
Koch, R
Surendran, S
Tyring, S
Matalon, R
Scriver, CR
Ugarte, M
Martínez, A
Stevens, RC
机构
[1] Univ Bergen, Dept Biomed, N-5009 Bergen, Norway
[2] McGill Univ, Montreal Childrens Hosp, Res Inst, Montreal, PQ H3H 1P3, Canada
[3] Univ Texas, Med Branch, Dept Pediat & Microbiol, Galveston, TX 77555 USA
[4] Childrens Hosp Los Angeles, Los Angeles, CA 90027 USA
[5] Univ Autonoma Madrid, Consejo Super Invest Cient, Ctr Biol Mol Severo Ochoa, E-28049 Madrid, Spain
[6] Scripps Res Inst, Dept Mol Biol, La Jolla, CA 92037 USA
关键词
D O I
10.1073/pnas.0407256101
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
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 tetra hydrobiopterin [(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, 165T, 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 K-m (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 IN 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.
引用
收藏
页码:16903 / 16908
页数:6
相关论文
共 50 条
[1]   2.0 Å 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].
Andersen, OA ;
Stokka, AJ ;
Flatmark, T ;
Hough, E .
JOURNAL OF MOLECULAR BIOLOGY, 2003, 333 (04) :747-757
[2]   Crystal structure of the ternary complex of the catalytic domain of human phenylalanine hydroxylase with tetrahydrobiopterin and 3-(2-thienyl)-L-alanine, and its implications for the mechanism of catalysis and substrate activation [J].
Andersen, OA ;
Flatmark, T ;
Hough, E .
JOURNAL OF MOLECULAR BIOLOGY, 2002, 320 (05) :1095-1108
[3]   High resolution crystal structures of the catalytic domain of human phenylalanine hydroxylase in its catalytically active Fe(II) form and binary complex with tetrahydrobiopterin [J].
Andersen, OA ;
Flatmark, T ;
Hough, E .
JOURNAL OF MOLECULAR BIOLOGY, 2001, 314 (02) :279-291
[4]   Mechanism of dioxygen cleavage in tetrahydrobiopterin-dependent amino acid hydroxylases [J].
Bassan, A ;
Blomberg, MRA ;
Siegbahn, PEM .
CHEMISTRY-A EUROPEAN JOURNAL, 2003, 9 (01) :106-115
[5]   High frequency of tetrahydrobiopterin-responsiveness among hyperphenylalaninemias: a study of 1919 patients observed from 1988 to 2002 [J].
Bernegger, C ;
Blau, N .
MOLECULAR GENETICS AND METABOLISM, 2002, 77 (04) :304-313
[6]   Partial characterization and three-dimensional structural localization of eight mutations in exon 7 of the human phenylalanine hydroxylase gene associated with phenylketonuria [J].
Bjorgo, E ;
Knappskog, PM ;
Martinez, A ;
Stevens, RC ;
Flatmark, T .
EUROPEAN JOURNAL OF BIOCHEMISTRY, 1998, 257 (01) :1-10
[7]   The metabolic and molecular bases of tetrahydroblopterin-responsive phenylalanine hydroxylase deficiency [J].
Blau, N ;
Erlandsen, H .
MOLECULAR GENETICS AND METABOLISM, 2004, 82 (02) :101-111
[8]   Tetrahydrobiopterin-responsive phenylalanine hydroxylase deficiency: Possible regulation of gene expression in a patient with the homozygous L48S mutation [J].
Blau, N ;
Trefz, FK .
MOLECULAR GENETICS AND METABOLISM, 2002, 75 (02) :186-187
[9]  
Brunger AT, 1998, ACTA CRYSTALLOGR D, V54, P905, DOI 10.1107/s0907444998003254
[10]  
de la Cruz F, 2001, CLIN PERINATOL, V28, P419