Cloning and functional characterization of the bona fide geranylgeranyl diphosphate synthase from the red algal seaweed Bangia fuscopurpurea

Abstract

Geranylgeranyl diphosphate (GGPP, C20) is a key metabolic intermediate shared by several vital metabolic pathways, including the biosynthesis of carotenoids, the phytol side chains of chlorophylls and tocopherols, and diterpenoids such as gibberellins. In plants, the biosynthesis of GGPP is catalyzed by GGPP synthases (GGPPSs), some of which also produce geranyl diphosphate (C10) as their side-products. Despite of the key role of GGPP as an essential metabolic hub for plant growth, development and acclimation, there are limited studies on its supply by GGPPS in land plants and, even rarely, in algae. Here, we report the cloning and functional characterization of a GGPPS (BfGGPPS) from the intertidal red algal seaweed Bangia fuscopurpurea. Our in vivo and in vitro assays collectively demonstrated that BfGGPPS is a bona fide GGPPS that produces GGPP as its only product. By yeast two-hybrid assay, BfGGPPS revealed its interaction with a putative phytoene synthase, the entry enzyme for carotenoid biosynthesis, indicating a possible mechanism modulating metabolic flux through protein-protein interaction in red algae. Our phylogenetic analysis suggests an early divergence of GGPPSs from red algae and the green lineages during evolution.