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The role of 2‐methyl‐6‐phytylbenzoquinone methyltransferase in determining tocopherol composition in Synechocystis sp. PCC6803
Author(s) -
Shintani David K.,
Cheng Zigang,
DellaPenna Dean
Publication year - 2002
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)03223-9
Subject(s) - methyltransferase , methylation , mutant , biochemistry , open reading frame , synechocystis , microbiology and biotechnology , gene , tocopherol , biology , enzyme , chemistry , peptide sequence , vitamin e , antioxidant
A putative 2‐methyl‐6‐phytylbenzoquinone (MPBQ) methyltransferase gene, SLL0418, was identified from the Synechocystis PCC6803 genome based on its homology to previously characterized γ‐tocopherol methyltransferases. Genetic and biochemical evidence confirmed open reading frame (ORF) SLL0418 encodes a MPBQ methyltransferase. An SLL0418 partial knockout mutant accumulated β‐tocopherol with no effect in the overall tocopherol content of the cell. In vitro assays of the SLL0418 gene expressed in Escherichia coli showed the enzyme efficiently catalyzes methylation of ring carbon 3 of MPBQ. In addition, the enzyme also catalyzes the methylation of ring carbon 3 of 2‐methyl‐6‐solanylbenzoquinol in the terminal step of plastoquinone biosynthesis.