Biophysical properties of UDP-glucose:glycoprotein glucosyltransferase, a folding sensor enzyme in the ER, delineated by synthetic probes.

Masafumi Sakono, Akira Seko, Yoichi Takeda, Masakazu Hachisu, Yukishige Ito

Japan Science and Technology Agency (JST), ERATO, Ito Glycotrilogy Project, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.

Biochemical and biophysical research communications 2012 Oct 5

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UDP-glucose:glycoprotein glucosyltransferase plays a key role in glycoprotein quality control in the endoplasmic reticulum, by virtue of its ability to discriminate folding states. Although lines of evidence have clarified the ability of UGGT to recognize a partially unfolded protein, its mechanistic rationale has been obscure. In this study, the substrate recognition mechanism of UGGT was studied using synthetic substrate of UGGT. Although UGGT has high extent of surface hydrophobicity, it clearly lacks property of typical molecular chaperones. Furthermore, it was revealed that the addition of the substrate caused secondary structure change of UGGT in a dose-dependent manner, resulting that the K(d) value of the UGGT-substrate interaction was estimated from theoretical formula based on 1:1 complexation between UGGT and the acceptor substrate. Moreover, the kinetic analysis of glucosyltransferase activity of UGGT elucidated Michaelis constant K(m) correctly. Copyright © 2012 Elsevier Inc. All rights reserved.

Citation

Masafumi Sakono, Akira Seko, Yoichi Takeda, Masakazu Hachisu, Yukishige Ito. Biophysical properties of UDP-glucose:glycoprotein glucosyltransferase, a folding sensor enzyme in the ER, delineated by synthetic probes. Biochemical and biophysical research communications. 2012 Oct 5;426(4):504-10