ATR-FTIR study of the protonation states of the Glu residue in the multicopper oxidases, CueO and bilirubin oxidase

作者：Iwaki Masayo^*; Kataoka Kunishige; Kajino Tsutomu; Sugiyama Ryosuke; Morishita Hirotoshi; Sakurai Takeshi

来源：FEBS Letters, 2010, 584(18): 4027-4031.

DOI：10.1016/j.febslet.2010.08.018

• Attenuated total reflectance-Fourier
• transform infrared
• Bilirubin oxidase
• CueO
• Multicopper oxidase
• Oxygen reduction
• Proton transfer

Redox-induced protonation state changes of the Glu residue in the multicopper oxidases, CueO and bilirubin oxidase (BO), were studied by attenuated total reflectance-Fourier transform infrared spectroscopy. By monitoring IR bands of the carboxylic acid C=O stretch in the wild-type and Gluto-Gln mutant enzymes the Glu506 of CueO (Glu463 of BO) was found to be unprotonated in the oxidised and protonated in the reduced forms. The results provided direct evidence for proton uptake by the Glu, suggesting it plays a key role in the proton donation to the activated oxygen species in the catalytic cycle.

• 出版日期2010-9-24