title: N-glycosylation and dimerization regulate the PtrMAN6 enzyme activity that may modulate generation of oligosaccharide signals.
abstract: PtrMAN6 is a plant mannan endo-hydrolase involved in modulating cell expansion and cell wall thickening in Populus developing xylem. N-glycosylation and dimerization affect the PtrMAN6 enzymatic activity, which is crucial for production of the endogenous galactoglucomannan oligosaccharide signal molecule in plants. There are 5 potential N-glycosylation sites and 6 cysteines in PtrMAN6 sequence. Each of the N-glycosylation or cysteine sites was site-direct mutagenized individually as well as in combination to analyze their effects on the PtrMAN6 N-glycosylation or dimerization status and the enzyme activity. Our results demonstrated that all 5 potential N-glycosylation sites are involved in the N-glycosylation, which is essential for PtrMAN6 enzyme activity. Meanwhile, we found only 3 carboxyl-terminal cysteines are involved in formation of disulfide-linked dimer to regulate PtrMAN6 activity. The 3 carboxyl-terminal cysteines were conserved in the wall-bounded mannan endo-hydrolases, and this structure may play a role in regulating the PtrMAN6 activity through interaction with redox signals such as reactive oxygen species (ROS) and hydrogen sulfide (H2S) for GGMOs signal generation.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics; CAS Key Laboratory of Synthetic Biology; Institute of Plant Physiology and Ecology; Shanghai Institutes for Biological Sciences; Chinese Academy of Sciences; Shanghai, PR China.
authors.forename: Yunjun
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: National Key Laboratory of Plant Molecular Genetics; CAS Key Laboratory of Synthetic Biology; Institute of Plant Physiology and Ecology; Shanghai Institutes for Biological Sciences; Chinese Academy of Sciences; Shanghai, PR China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: National Key Laboratory of Plant Molecular Genetics; CAS Key Laboratory of Synthetic Biology; Institute of Plant Physiology and Ecology; Shanghai Institutes for Biological Sciences; Chinese Academy of Sciences; Shanghai, PR China.
authors.forename: Luxia
authors.initials: L
authors.lastname: Yuan
authors.affiliation: National Key Laboratory of Plant Molecular Genetics; CAS Key Laboratory of Synthetic Biology; Institute of Plant Physiology and Ecology; Shanghai Institutes for Biological Sciences; Chinese Academy of Sciences; Shanghai, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.affiliation: National Key Laboratory of Plant Molecular Genetics; CAS Key Laboratory of Synthetic Biology; Institute of Plant Physiology and Ecology; Shanghai Institutes for Biological Sciences; Chinese Academy of Sciences; Shanghai, PR China.
authors.forename: Laigeng
authors.initials: L
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D003545:Cysteine / Q000378:metabolism; D019281:Dimerization; D004220:Disulfides / Q000378:metabolism; D006031:Glycosylation; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000378:metabolism*; D010084:Oxidation-Reduction; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D032107:Populus / Q000201:enzymology*; D015398:Signal Transduction; D013329:Structure-Activity Relationship
chemical_list: D004220:Disulfides; D009844:Oligosaccharides; D010940:Plant Proteins; D003545:Cysteine
keywords: Dimerization; GGMOs; N-glycosylation; PtrMAN6; Redox