Abstract
Dopa decarboxylase (DDC or AADC) is a pyridoxal 5’-phosphate (PLP)-dependent enzyme that catalyzes the decarboxylation of L-aromatic amino acids into the corresponding aromatic amines. AADC deficiency is an inborn error of neurotransmitters biosynthesis with an autosomal recessive inheritance. About 30 pathogenic mutations have been identified, but the enzymatic phenotypes causing AADC deficiency are unknown, and the therapeutic management is challenging. Here, we report biochemical and bioinformatic analyses of the human wild-type DDC and the pathogenic variants G102S, F309L, S147R and A275T whose mutations concern amino acid residues at or near the active site. We found that the mutations cause, even if to different extents, a decreased PLP binding affinity (in the range 1.4-170-fold), an altered state of the bound coenzyme and of its microenvironment, and a reduced catalytic efficiency (in the range 17-930-fold). Moreover, as compared to wild-type, the external aldimines formed by the variants with L-aromatic amino acids exhibit different spectroscopic features, do not protect against limited proteolysis, and lead to the formation, in addition to aromatic amines, of cyclic-substrate adducts. This suggests that these external Schiff bases are not properly oriented and anchored, i.e., in a conformation not completely productive for decarboxylation. The external aldimines that the variants form with D-Dopa also appear not to be correctly located at their active site, as suggested by the rate constants of PLP-L-Dopa adduct production higher than that of the wild-type. The possible therapeutic implications of the data are discussed in the light of the molecular defects of the pathogenic variants.
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Abbreviations
- PLP:
-
Pyridoxal 5’-phosphate
- DDC:
-
Dopa decarboxylase
- L-5-HTP:
-
L-5-hydroxytryptophan
- TNB:
-
2,4,6-trinitrobenzene-1-sulfonic acid
References
Allen GF, Land JM, Heales SJ (2009) A new perspective on the treatment of aromatic L-amino acid decarboxylase deficiency. Mol Genet Metab 97:6–14
Bertoldi M, Dominici P, Moore PS, Maras B, Voltattorni BC (1998) Reaction of dopa decarboxylase with alpha-methyldopa leads to an oxidative deamination producing 3,4-dihydroxyphenylacetone, an active site directed affinity label. Biochemistry 37:6552–6561
Bertoldi M, Frigeri P, Paci M, Voltattorni Borri C (1999) Reaction specificity of native and nicked 3,4-dihydroxyphenylalanine decarboxylase. J Biol Chem 274:5514–5521
Bertoldi M, Gonsalvi M, Contestabile R, Voltattorni Borri C (2002) Mutation of tyrosine 332 to phenylalanine converts dopa decarboxylase into a decarboxylation-dependent oxidative deaminase. J Biol Chem 277:36357–36362
Bertoldi M, Moore PS, Maras B, Dominici P, Voltattorni Borri C (1996) Mechanism-based inactivation of dopa decarboxylase by serotonin. J Biol Chem 271:23954–23959
Brun L, Ngu LH, Keng WT et al (2010) Clinical and biochemical features of aromatic L-amino acid decarboxylase deficiency. Neurology 75:64–71
Burkhard P, Dominici P, Voltattorni Borri C, Jansonius JN, Malashkevich VN (2001) Structural insight into Parkinson's disease treatment from drug-inhibited DOPA decarboxylase. Nat Struct Biol 8:963–967
Chang YT, Mues G, Mcpherson J Bedell J L. Marsh, Hyland K (1998) Mutations in the human aromatic L-amino acid decarboxylase gene. J Inherit Metab Dis 21
Chang YT, Sharma R, Marsh JL et al (2004) Levodopa-responsive aromatic L-amino acid decarboxylase deficiency. Ann Neurol 55:435–438
Charteris A, John R (1975) An investigation of the assay of dopamine using trinitrobenzensulphonic acid. Anal Biochem 66:365–371
De Lano W (2002) The PyMol Molecular Graphics System. De Lano Scientifics, San Carlos, CA
Dominici P, Moore PS, Voltattorni Borri C (1993) Dissociation, unfolding and refolding trials of pig kidney 3,4-dihydroxyphenylalanine (dopa) decarboxylase. Biochem J 295(Pt 2):493–500
Dominici P, Moore PS, Castellani S, Bertoldi M, Voltattorni Borri C (1997) Mutation of cysteine 111 in Dopa decarboxylase leads to active site perturbation. Protein Sci 6:2007–2015
Dominici P, Tancini B, Barra D, Voltattorni Borri C (1987) Purification and characterization of rat-liver 3,4-dihydroxyphenylalanine decarboxylase. Eur J Biochem 169:209–213
Dominici P, Tancini B, Voltattorni Borri C (1985) Chemical modification of pig kidney 3,4-dihydroxyphenylalanine decarboxylase with diethyl pyrocarbonate. Evidence for an essential histidyl residue. J Biol Chem 260:10583–10589
Hayashi H, Mizuguchi H, Kagamiyama H (1993) Rat liver aromatic L-amino acid decarboxylase: spectroscopic and kinetic analysis of the coenzyme and reaction intermediates. Biochemistry 32:812–818
Hyland K, Clayton PT (1990) Aromatic amino acid decarboxylase deficiency in twins. J Inherit Metab Dis 13:301–304
Hyland K, Clayton PT (1992) Aromatic L-amino acid decarboxylase deficiency: diagnostic methodology. Clin Chem 38:2405–2410
Hyland K, Surtees RA, Rodeck C, Clayton PT (1992) Aromatic L-amino acid decarboxylase deficiency: clinical features, diagnosis, and treatment of a new inborn error of neurotransmitter amine synthesis. Neurology 42:1980–1988
Lee HF, Tsai CR, Chi CS, Chang TM, Lee HJ (2009) Aromatic L-amino acid decarboxylase deficiency in Taiwan. Eur J Paediatr Neurol 13:135–140
Manegold C, Hoffmann GF, Degen I et al (2009) Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up. J Inherit Metab Dis 32:371–380
Maras B, Dominici P, Barra D, Bossa F, Voltattorni Borri C (1991) Pig kidney 3,4-dihydroxyphenylalanine (dopa) decarboxylase. Primary structure and relationships to other amino acid decarboxylases. Eur J Biochem 201:385–391
Moore PS, Dominici P, Voltattorni Borri C (1996) Cloning and expression of pig kidney dopa decarboxylase: comparison of the naturally occurring and recombinant enzymes. Biochem J 315:249–256
Pons R, Ford B, Chiriboga CA et al (2004) Aromatic L-amino acid decarboxylase deficiency: clinical features, treatment, and prognosis. Neurology 62:1058–1065
Sherald AF, Sparrow JC, Wright TR (1973) A spectrophotometric assay for Drosophila dopa decarboxylase. Anal Biochem 56:300–305
Streffer C (1967) A method for determining aromatic amino acid decarboxylase. Biochim Biophys Acta 139:193–195
Tancini B, Dominici P, Simmaco M, Schinina ME, Barra D, Voltattorni Borri C (1988) Limited tryptic proteolysis of pig kidney 3,4-dihydroxyphenylalanine decarboxylase. Arch Biochem Biophys 260:569–576
Voltattorni Borri C, Minelli A, Dominici P (1983) Interaction of aromatic amino acids in D and L forms with 3,4-dihydroxyphenylalanine decarboxylase from pig kidney. Biochemistry 22:2249–2254
Voltattorni Borri C, Minelli A, Turano C (1971) Spectral properties of the coenzyme bound to DOPA decarboxylase from pig kidney. FEBS Lett 17:231–235
Voltattorni Borri C, Minelli A, Vecchini P, Fiori A, Turano C (1979) Purification and characterization of 3,4-dihydroxyphenylalanine decarboxyase from pig kidney. Eur J Biochem 93:181–188
Acknowledgments
This work was supported by grants from M.I.U.R. (Prin 2007) to (C.B.V.). The skilful technical assistance of Silvia Bianconi is acknowledged.
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Communicated by: K. Michael Gibson
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Figure 1SM
Superimposition of the structure of wild type (gray) and (A) G102S, (B) F309L, (C) S147R and (D) A275T mutants (purple), obtained by an in silico energy minimization analysis. In each case the mutated residue and the PLP molecule are represented as yellow and green sticks respectively. H-bonds as dotted line, phosphorus, oxygen and nitrogen atoms are colored orange, red and blue, respectively. In panel B the residues belonging to the hydrophobic and the polar cavity are represented as blue and red sticks respectively. Picture was created by means Pymol software (DeLano Scientific) (JPEG 139 kb)
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Montioli, R., Cellini, B. & Borri Voltattorni, C. Molecular insights into the pathogenicity of variants associated with the aromatic amino acid decarboxylase deficiency. J Inherit Metab Dis 34, 1213–1224 (2011). https://doi.org/10.1007/s10545-011-9340-6
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DOI: https://doi.org/10.1007/s10545-011-9340-6