A Novel Hydrolytic Activity of Tri-Functional Geranylgeranyl Pyrophosphate Synthase in Haematococcus pluvialis

Abstract

Under environmental stresses, Haematococcus pluvialis accumulates large amounts of carotenoids. Scale of carotenoid biosynthesis depends on availability of geranylgeranyl pyrophosphate (GGPP) precursor, which is supplied by GGPP synthase (GGPPS) through sequential 1'-4 condensation of three isopentenyl pyrophosphates (IPPs) into dimethylallyl pyrophosphate (DMAPP). Using IPP and DMAPP as substrates, a tri-functional HpGGPPS was identified in this study to promiscuously synthesize allylic prenyl pyrophosphates (PPPs), e.g., C10 geranyl pyrophosphate (GPP), C15 farnesyl pyrophosphate (FPP), and C20 GGPP. Intriguingly, HpGGPPS can utilize GPP or FPP as a single substrate to synthesize GGPP by hydrolyzing the allylic PPP substrate into C5 IPP. Transcription of HpGGPPS and key carotenogenesis genes, morphological transformation, and carotenoid biosynthesis were differentially induced by environmental stresses, while HpGGPPS's products were low in vivo, implying that most of PPP flux had been shunted into carotenoid biosynthesis. Hydrolyzing allylic PPP intermediates into C5 building blocks by promiscuous HpGGPPS may be a fail safe for carotenoid accumulation against environmental stress.

Discovery of Geranylgeranyl Pyrophosphate Synthase (GGPPS) Paralogs from Haematococcus pluvialis Based on Iso-Seq Analysis and Their Function on Astaxanthin Biosynthesis

“…Sequence similarity analysis showed that HpGGPPS1-1 and HpGGPPS1-2 shared 99% identity in nucleotides of coding region and only one amino acid differences. By contrast, big variation (90% identity) was found in the 5'UTR region of HpGGPPS1-1 and HpGGPPS1-2, indicating there are two functional HpGGPPS in H. pluvialis rather than one as previously reported [35]. No astaxanthin or other visible pigments were observed in E. coli carrying the rest of six HpGGPPS candidates, indicating they might not directly associate with astaxanthin production.…”

Transcriptome Analysis of the Accumulation of Astaxanthin in Haematococcus pluvialis Treated with White and Blue Lights as well as Salicylic Acid

“…Moreover, our results of qRT-PCR analysis showed that the expression of psy was significantly increased in H . pluvialis treated with white light for 7 days, while PSY played a key role in the extension of the carbon chain in the synthesis of astaxanthin [ 45 ]. Additionally, the expression of the lyc gene is directly related to the synthesis of β -carotene.…”

Biosynthesis and extraction of high-value carotenoid from algae

“…In the initial step, 10-carbon compound sesquiterpene is synthesized by the addition of one IPP and one DMAPP molecule. In subsequent steps, FPP is synthesized by the addition of one IPP molecule to sesquiterpene and then GGPP is formed by the addition of one more IPP molecule to FPP (farnesyl pyrophosphate) [67,68]. This process involves three different types of enzymes: GPPS-geranyl diphosphate synthase, FPPS-farnesyl diphosphate synthase, and GGPPS-geranylgeranyl diphosphate synthase, sequentially [65].…”

“…They reported that a polypeptide sequence of 345 amino acids with transit peptide sequence (N-terminal) is encoded by this gene. Lao et al [67] reported that, GGPPS of an alga Haematococcus pluvialis (HpGGPPS) have tri-functional catalytic activities, which catalyzes all three steps of GGPP biosynthesis. Deng et al [58] cloned and characterize the bfGGPPS from the red alga Bangia fuscopurpurea.…”