2-甲基-6-植基苯醌甲基转移酶在决定集胞藻PCC6803生育酚组成中的作用

The role of 2-methyl-6-phytylbenzoquinone methyltransferase in determining tocopherol composition in Synechocystis sp. PCC6803.

作者信息

Shintani David K, Cheng Zigang, DellaPenna Dean

机构信息

Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA.

出版信息

FEBS Lett. 2002 Jan 30;511(1-3):1-5. doi: 10.1016/s0014-5793(01)03223-9.

DOI:10.1016/s0014-5793(01)03223-9

PMID:11821038

Abstract

A putative 2-methyl-6-phytylbenzoquinone (MPBQ) methyltransferase gene, SLL0418, was identified from the Synechocystis PCC6803 genome based on its homology to previously characterized gamma-tocopherol methyltransferases. Genetic and biochemical evidence confirmed open reading frame (ORF) SLL0418 encodes a MPBQ methyltransferase. An SLL0418 partial knockout mutant accumulated beta-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.

摘要

基于与先前鉴定的γ-生育酚甲基转移酶的同源性，从集胞藻PCC6803基因组中鉴定出一个假定的2-甲基-6-植基苯醌（MPBQ）甲基转移酶基因SLL0418。遗传和生化证据证实开放阅读框（ORF）SLL0418编码一种MPBQ甲基转移酶。SLL0418部分敲除突变体积累了β-生育酚，对细胞中总生育酚含量没有影响。在大肠杆菌中表达的SLL0418基因的体外试验表明，该酶能有效催化MPBQ第3环碳原子的甲基化。此外，该酶还在质体醌生物合成的最后一步催化2-甲基-6-茄尼基苯醌第3环碳原子的甲基化。