title: Structural insights into the methyl donor recognition model of a novel membrane-binding protein UbiG.
abstract: UbiG is a SAM-dependent O-methyltransferase, catalyzing two O-methyl transfer steps for ubiquinone biosynthesis in Escherichia coli. UbiG possesses a unique sequence insertion between β4 and α10, which is used for membrane lipid interaction. Interestingly, this sequence insertion also covers the methyl donor binding pocket. Thus, the relationship between membrane binding and entrance of the methyl donor of UbiG during the O-methyl transfer process is a question that deserves further exploration. In this study, we reveal that the membrane-binding region of UbiG gates the entrance of methyl donor. When bound with liposome, UbiG displays an enhanced binding ability toward the methyl donor product S-adenosylhomocysteine. We further employ protein engineering strategies to design UbiG mutants by truncating the membrane interacting region or making it more flexible. The ITC results show that the binding affinity of these mutants to SAH increases significantly compared with that of the wild-type UbiG. Moreover, we determine the structure of UbiG∆(165-187) in complex with SAH. Collectively, our results provide a new angle to cognize the relationship between membrane binding and entrance of the methyl donor of UbiG, which is of benefit for better understanding the O-methyl transfer process for ubiquinone biosynthesis.
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, Innovation Center for Cell Signaling Network, School of Life Science, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China.|Key Laboratory of Structural Biology, Hefei Science Center of CAS, Chinese Academy of Science, Hefei, Anhui, 230026, People's Republic of China.
authors.forename: Yuwei
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, Innovation Center for Cell Signaling Network, School of Life Science, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China.|Key Laboratory of Structural Biology, Hefei Science Center of CAS, Chinese Academy of Science, Hefei, Anhui, 230026, People's Republic of China.
authors.forename: Xuguang
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, Innovation Center for Cell Signaling Network, School of Life Science, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China.|Key Laboratory of Structural Biology, Hefei Science Center of CAS, Chinese Academy of Science, Hefei, Anhui, 230026, People's Republic of China.
authors.forename: Chongyuan
authors.initials: C
authors.lastname: Wang
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, Innovation Center for Cell Signaling Network, School of Life Science, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China.|Key Laboratory of Structural Biology, Hefei Science Center of CAS, Chinese Academy of Science, Hefei, Anhui, 230026, People's Republic of China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, Innovation Center for Cell Signaling Network, School of Life Science, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China.|Key Laboratory of Structural Biology, Hefei Science Center of CAS, Chinese Academy of Science, Hefei, Anhui, 230026, People's Republic of China.
authors.forename: Xiaojiao
authors.initials: X
authors.lastname: Fan
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, Innovation Center for Cell Signaling Network, School of Life Science, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China.|Key Laboratory of Structural Biology, Hefei Science Center of CAS, Chinese Academy of Science, Hefei, Anhui, 230026, People's Republic of China.
authors.forename: Linjuan
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, Innovation Center for Cell Signaling Network, School of Life Science, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China.|Key Laboratory of Structural Biology, Hefei Science Center of CAS, Chinese Academy of Science, Hefei, Anhui, 230026, People's Republic of China.
authors.forename: Liwen
authors.initials: L
authors.lastname: Niu
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, Innovation Center for Cell Signaling Network, School of Life Science, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China.|Key Laboratory of Structural Biology, Hefei Science Center of CAS, Chinese Academy of Science, Hefei, Anhui, 230026, People's Republic of China.
authors.forename: Maikun
authors.initials: M
authors.lastname: Teng
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, Innovation Center for Cell Signaling Network, School of Life Science, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China.|Key Laboratory of Structural Biology, Hefei Science Center of CAS, Chinese Academy of Science, Hefei, Anhui, 230026, People's Republic of China.
authors.forename: Xu
authors.initials: X
authors.lastname: Li
mesh_terms: D003460:Crystallization; D003461:Crystallography; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008780:Methyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D012435:S-Adenosylhomocysteine / Q000737:chemistry
chemical_list: D029968:Escherichia coli Proteins; D012435:S-Adenosylhomocysteine; D008780:Methyltransferases; C019616:UbiG protein, E coli