TY - JOUR
T1 - Computational exploration of the catalytic mechanism of dopamine β-monooxygenase
T2 - Modeling of its mononuclear copper active sites
AU - Kamachi, Takashi
AU - Kihara, Naoki
AU - Shiota, Yoshihito
AU - Yoshizawa, Kazunari
PY - 2005/6/13
Y1 - 2005/6/13
N2 - Dopamine hydroxylation by the copper-superoxo, -hydroperoxo, and -oxo species of dopamine β-monooxygenase (DBM) is investigated using theoretical calculations to identify the active species in its reaction and to reveal the key functions of the surrounding amino acid residues in substrate binding. A 3D model of rat DBM is constructed by homology modeling using the crystal structure of peptidylglycine α-hydroxylating monooxygenase (PHM) with a high sequence identity of 30% as a template. In the constructed 3D model, the CuA site in domain 1 is coordinated by three histidine residues, His265, His266, and His336, while the CuB site in domain 2 is coordinated by two histidine residues, His415 and His417, and by a methionine residue, Met490. The three Glu268, Glu369, and Tyr494 residues are suggested to play an important role in the substrate binding at the active site of DBM to enable the stereospecific hydrogen-atom abstraction. Quantum mechanical/molecular mechanical (QM/MM) calculations are performed to determine the structure of the copper-superoxo, -hydroperoxo, and -oxo species in the whole-enzyme model with about 4700 atoms. The reactivity of the three oxidants is evaluated in terms of density-functional-theory calculations with small models extracted from the QM region of the whole-enzyme model.
AB - Dopamine hydroxylation by the copper-superoxo, -hydroperoxo, and -oxo species of dopamine β-monooxygenase (DBM) is investigated using theoretical calculations to identify the active species in its reaction and to reveal the key functions of the surrounding amino acid residues in substrate binding. A 3D model of rat DBM is constructed by homology modeling using the crystal structure of peptidylglycine α-hydroxylating monooxygenase (PHM) with a high sequence identity of 30% as a template. In the constructed 3D model, the CuA site in domain 1 is coordinated by three histidine residues, His265, His266, and His336, while the CuB site in domain 2 is coordinated by two histidine residues, His415 and His417, and by a methionine residue, Met490. The three Glu268, Glu369, and Tyr494 residues are suggested to play an important role in the substrate binding at the active site of DBM to enable the stereospecific hydrogen-atom abstraction. Quantum mechanical/molecular mechanical (QM/MM) calculations are performed to determine the structure of the copper-superoxo, -hydroperoxo, and -oxo species in the whole-enzyme model with about 4700 atoms. The reactivity of the three oxidants is evaluated in terms of density-functional-theory calculations with small models extracted from the QM region of the whole-enzyme model.
UR - http://www.scopus.com/inward/record.url?scp=20744452335&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=20744452335&partnerID=8YFLogxK
U2 - 10.1021/ic048477p
DO - 10.1021/ic048477p
M3 - Article
C2 - 15934751
AN - SCOPUS:20744452335
VL - 44
SP - 4226
EP - 4236
JO - Inorganic Chemistry
JF - Inorganic Chemistry
SN - 0020-1669
IS - 12
ER -