Int. J. Mol. Sci. 2013, 14(1), 1218-1231; doi:10.3390/ijms14011218
Article

Catalytic Mechanism of Short Ethoxy Chain Nonylphenol Dehydrogenase Belonging to a Polyethylene Glycol Dehydrogenase Group in the GMC Oxidoreductase Family

Xin Liu 1,† email, Takeshi Ohta 2,† email, Takeshi Kawabata 3 email and Fusako Kawai 4,* email
1 Urban and Environmental Science College, Liaoning Normal University, Dalian 116029, China 2 Department of Life Science, Faculty of Life and Environmental Sciences, Hiroshima Prefectural University, Shobara, Hiroshima 727-0023, Japan 3 Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan 4 Center for Nanomaterials and Devices, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan † These authors contributed equally to this work.
* Author to whom correspondence should be addressed.
Received: 10 October 2012; in revised form: 21 December 2012 / Accepted: 2 January 2013 / Published: 10 January 2013
(This article belongs to the Special Issue Flavins)
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Abstract: Ethoxy (EO) chain nonylphenol dehydrogenase (NPEO-DH) from Ensifer sp. AS08 and EO chain octylphenol dehydrogenase from Pseudomonas putida share common molecular characteristics with polyethylene glycol (PEG) dehydrogenases (PEG-DH) and comprise a PEG-DH subgroup in the family of glucose-methanol-choline (GMC) oxidoreductases that includes glucose/alcohol oxidase and glucose/choline dehydrogenase. Three-dimensional (3D) molecular modeling suggested that differences in the size, secondary structure and hydropathy in the active site caused differences in their substrate specificities toward EO chain alkylphenols and free PEGs. Based on 3D molecular modeling, site-directed mutagenesis was utilized to introduce mutations into potential catalytic residues of NPEO-DH. From steady state and rapid kinetic characterization of wild type and mutant NPEO-DHs, we can conclude that His465 and Asn507 are directly involved in the catalysis. Asn507 mediates the transfer of proton from a substrate to FAD and His465 transfers the same proton from the reduced flavin to an electron acceptor.
Keywords: GMC oxidoreductase family; polyethylene glycol dehydrogenase; ethoxy chain nonylphenol/octylphenol dehydrogenase; catalytic site; Ensifer sp. AS08

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MDPI and ACS Style

Liu, X.; Ohta, T.; Kawabata, T.; Kawai, F. Catalytic Mechanism of Short Ethoxy Chain Nonylphenol Dehydrogenase Belonging to a Polyethylene Glycol Dehydrogenase Group in the GMC Oxidoreductase Family. Int. J. Mol. Sci. 2013, 14, 1218-1231.

AMA Style

Liu X, Ohta T, Kawabata T, Kawai F. Catalytic Mechanism of Short Ethoxy Chain Nonylphenol Dehydrogenase Belonging to a Polyethylene Glycol Dehydrogenase Group in the GMC Oxidoreductase Family. International Journal of Molecular Sciences. 2013; 14(1):1218-1231.

Chicago/Turabian Style

Liu, Xin; Ohta, Takeshi; Kawabata, Takeshi; Kawai, Fusako. 2013. "Catalytic Mechanism of Short Ethoxy Chain Nonylphenol Dehydrogenase Belonging to a Polyethylene Glycol Dehydrogenase Group in the GMC Oxidoreductase Family." Int. J. Mol. Sci. 14, no. 1: 1218-1231.

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