ENZYMATIC CYCLIZATION OF ALL-TRANS PENTAPRENYL AND HEXAPRENYL METHYL ETHERS BY A CELL-FREE SYSTEM FROM THE PROTOZOAN TETRAHYMENA-PYRIFORMIS - THE BIOSYNTHESIS OF SCALARANE AND POLYCYCLOHEXAPRENYL DERIVATIVES
ENZYMATIC CYCLIZATION OF ALL-TRANS PENTAPRENYL AND HEXAPRENYL METHYL ETHERS BY A CELL-FREE SYSTEM FROM THE PROTOZOAN TETRAHYMENA-PYRIFORMIS - THE BIOSYNTHESIS OF SCALARANE AND POLYCYCLOHEXAPRENYL DERIVATIVES
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DOI：
10.1111/j.1432-1033.1986.tb09467.x
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发表时间：
1986-02-17
期刊：
影响因子：
--
通讯作者：
ROHMER, M
中科院分区：
文献类型：
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作者：
RENOUX, JM;ROHMER, M
能够将角鲨烯环化成四海曼醇的原生动物梨形四膜虫的无细胞系统将全反式戊异戊二烯基甲基醚环化成scalarane型二倍半萜烯，并将全反式六异戊二烯基甲基醚环化成双环-、三环-、四环-和五环六异戊二烯基甲基醚，每一种对应于可能的阳离子中间体。环化产物的结构已被确定的光谱方法，并与涉及聚异戊二烯醚环化的生物遗传学计划是兼容的。这是第一个直接证明的酶环化的高级异戊二烯醇衍生物，我们假设它是由原生动物的角鲨烯到环化酶。从C25聚异戊二烯基甲基醚的scalarane型二倍半萜的形成表明，这些萜类化合物，其存在仅限于少数海绵，可能实际上是微生物代谢产物。三环聚异戊二烯衍生物已在许多沉积物的有机质中被鉴定出来，它们被解释为尚未鉴定的微生物的化学化石。六异戊二烯基甲基醚的环化反应是首次尝试在生物体中鉴定这些三环聚异戊二烯醇衍生物。
A cell-free system from the protozoan Tetrahymena pyriformis capable of cyclizing squalene into tetrahymanol cyclizes all-trans pentaprenyl methyl ether to a scalarane-type sesterterpene and all-trans hexaprenyl methyl ether to bicyclo-, tricyclo-, tetracyclo- and pentacyclohexaprenyl methyl ethers, each corresponding to a possible cationic intermediate. The structures of the cyclization products have been determined by spectroscopic methods and are compatible with a biogenetic scheme involving polyprenyl ether cyclization. This is the first direct proof of an enzymatic cyclization of higher isoprenic alcohol derivatives, and we assume it was performed by the squalene-to-hopane cyclase of the protozoon. The formation of a scalarane-type sesterterpene from C25 polyprenyl methyl ether suggests that these terpenoids, whose presence is restricted to a few sponges, might be in fact microbial metabolites. Tricyclopolyprenyl derivatives have been identified in the organic matter from numerous sediments and they were interpreted as being chemical fossils of still unidentified microorganisms. The cyclization of hexaprenyl methyl ether is the first attempt of identification of these tricyclopolyprenol derivatives in living organisms.