National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM56838
米国
引用
ジャーナル: Proc Natl Acad Sci U S A / 年: 2024 タイトル: Engineering substrate channeling in a bifunctional terpene synthase. 著者: Eliott S Wenger / Kollin Schultz / Ronen Marmorstein / David W Christianson / 要旨: Fusicoccadiene synthase from (PaFS) is a bifunctional terpene synthase. It contains a prenyltransferase (PT) domain that generates geranylgeranyl diphosphate (GGPP) from dimethylallyl diphosphate ...Fusicoccadiene synthase from (PaFS) is a bifunctional terpene synthase. It contains a prenyltransferase (PT) domain that generates geranylgeranyl diphosphate (GGPP) from dimethylallyl diphosphate and three equivalents of isopentenyl diphosphate, and a cyclase domain that converts GGPP into fusicoccadiene, a precursor of the diterpene glycoside Fusicoccin A. The two catalytic domains are connected by a flexible 69-residue linker. The PT domain mediates oligomerization to form predominantly octamers, with cyclase domains randomly splayed out around the PT core. Surprisingly, despite the random positioning of cyclase domains, substrate channeling is operative in catalysis since most of the GGPP generated by the PT remains on the enzyme for cyclization. Here, we demonstrate that covalent linkage of the PT and cyclase domains is not required for GGPP channeling, although covalent linkage may improve channeling efficiency. Moreover, GGPP competition experiments with other diterpene cyclases indicate that the PaFS PT and cyclase domains are preferential partners regardless of whether they are covalently linked or not. The cryoelectron microscopy structure of the 600-kD "linkerless" construct, in which the 69-residue linker is spliced out and replaced with the tripeptide PTQ, reveals that cyclase pairs associate with all four sides of the PT octamer and exhibit fascinating quaternary structural flexibility. These results suggest that optimal substrate channeling is achieved when a cyclase domain associates with the side of the PT octamer, regardless of whether the two domains are covalently linked and regardless of whether this interaction is transient or locked in place.
全体 : Octameric prenyltransferase core of linkerless Fusicoccadiene syn...
全体
名称: Octameric prenyltransferase core of linkerless Fusicoccadiene synthase with two associated cyclase domains
要素
複合体: Octameric prenyltransferase core of linkerless Fusicoccadiene synthase with two associated cyclase domains
タンパク質・ペプチド: Fusicoccadiene synthase (linkerless)
-
超分子 #1: Octameric prenyltransferase core of linkerless Fusicoccadiene syn...
超分子
名称: Octameric prenyltransferase core of linkerless Fusicoccadiene synthase with two associated cyclase domains タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: all 詳細: Linkerless Fusicoccadiene synthase was generated by replacing the native 70-residue linker region of the bifunctional enzyme with the tripeptide PTQ