Detoxification function of the Arabidopsis sulphotransferase AtSOT12 by sulphonation of xenobiotics.
Cytosolic sulphotransferases have been implicated in inactivation of endogenous steroid hormones and detoxification of xenobiotics in human and animals. Yet, the function of plant sulphotransferases in xenobiotic sulphonation and detoxification has not been reported. In this study, we show that the Arabidopsis sulphotransferase AtSOT12 could sulphonate the bacterial-produced toxin cycloheximide. Loss-of-function mutant sot12 exhibited hypersensitive phenotype to cycloheximide, and expression of AtSOT12 protein in yeast cells conferred resistance to this toxic compound. AtSOT12 exhibited broad specificity and could sulphonate a variety of xenobiotics including phenolic and polycyclic compounds. Enzyme kinetics analysis indicated that AtSOT12 has different selectivity for simple phenolics with different side chains, and the position of the side chain in the simple phenolic compounds affects substrate binding affinity and catalytic efficiency. We proposed that the broad specificity and induced production of AtSOT12 may have rendered this enzyme to not only modify endogenous molecules such as salicylic acid as we previously reported, but also sulphonate pathogen-produced toxic small molecules to protect them from infection. Sulphonation of small molecules in plants may constitute a rapid way to inactivate or change the physiochemical properties of biologically active molecules that could have profound effects on plant growth, development and defence.
Pre-National Laboratory for Crop Germplasm Innovation and Resource Utilization, Hunan Agricultural University, Changsha, Hunan, 410128, China.
Jinhua
J
Chen
Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA.
Liqiong
L
Gao
Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA.
Dongwon
D
Baek
Pre-National Laboratory for Crop Germplasm Innovation and Resource Utilization, Hunan Agricultural University, Changsha, Hunan, 410128, China.
Chunlin
C
Liu
Pre-National Laboratory for Crop Germplasm Innovation and Resource Utilization, Hunan Agricultural University, Changsha, Hunan, 410128, China.
Ying
Y
Ruan
Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA.
Huazhong
H
Shi
D000222:Adaptation, Physiological / Q000187:drug effects; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology; D008658:Inactivation, Metabolic / Q000187:drug effects; D007700:Kinetics; D010636:Phenols / Q000737:chemistry / Q000378:metabolism; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism; D013379:Substrate Specificity / Q000187:drug effects; D013451:Sulfonic Acids / Q000378:metabolism; D015238:Sulfotransferases / Q000378:metabolism*; D015262:Xenobiotics / Q000378:metabolism*
D029681:Arabidopsis Proteins; D010636:Phenols; D011084:Polycyclic Aromatic Hydrocarbons; D013451:Sulfonic Acids; D015262:Xenobiotics; D003513:Cycloheximide; C521808:ST1 protein, Arabidopsis; D015238:Sulfotransferases
Cycloheximide; Enzyme kinetics; Sulphate conjugation; plant defence