Crystal structure of the CueO mutants at Glu506, the key amino acid located in the proton transfer pathway for dioxygen reduction.
Glu506 involved in the hydrogen bond network leading from solvent waters to the trinuclear copper center in a multicopper oxidase, CueO plays a crucial role to transport protons in the four-electron reduction of dioxygen to water. We performed X-ray crystal structure analyses of the Glu506Ala and Glu506Ile mutants, showing the formation of a compensatory proton transport pathway with only water molecules and a disruption of the hydrogen bond network due to the bulky side chain, respectively. We discuss the efficiency of proton transport through the hydrogen bond network based on the present results and our previous modification of the proton transport pathway by the Glu506 to Gln mutation, which have allowed us to trap and characterize the reaction intermediates.
Faculty of Education, Kagawa University, 1-1 Saiwai, Takamatsu 760-8522, Japan.
Hirofumi
H
Komori
Takao
T
Kajikawa
Kunishige
K
Kataoka
Yoshiki
Y
Higuchi
Takeshi
T
Sakurai
D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D011487:Protein Conformation; D011522:Protons
D029968:Escherichia coli Proteins; D011522:Protons; D010088:Oxidoreductases; C499679:cueO protein, E coli; D010100:Oxygen
CueO; Hydrogen bond network; MCO; Multicopper oxidase; O(2)-reduction; Proton transfer; Site-directed mutagenesis; T1; T2; T3; TNC; X-ray crystal structure; multicopper oxidase; trinuclear copper center; type I; type II; type III