The stereochemistry of rubber biosynthesis

1966 ◽  
Vol 163 (993) ◽  
pp. 519-523 ◽  
Keyword(s):  
Natural Rubber ◽  
Farnesyl Pyrophosphate ◽  
Isopentenyl Pyrophosphate ◽  
Rubber Biosynthesis

The stereochemistry of the formation of natural rubber and trans-trans -farnesyl pyrophosphate in latex has been studied in vitro using [2- 14 C-(4 R )-4- 3 H 1 ] and [2- 14 C-(4 S )-4- 3 H 1 ]mevalonates as substrates. The proton eliminated from C-2 of isopentenyl pyrophosphate during the formation of farnesyl pyrophosphate in latex has the same steric position as that released in the liver system, and is epimeric with that eliminated during the biosynthesis of rubber. Complete stereospecificity is exhibited by the enzymes in the two cases. In rubber biosynthesis isoprene residues are incorporated directly in an all- cis configuration without the intervention of trans structures.

Stereochemistry of Rubber Biosynthesis

1967 ◽  
Vol 40 (3) ◽  
pp. 679-683
Author(s):  
B. L. Archer ◽  
D. Barnard ◽  
E. G. Cockbain ◽  
J. W. Cornforth ◽  
Rita H. Cornforth ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Farnesyl Pyrophosphate ◽  
Isopentenyl Pyrophosphate ◽  
Rubber Biosynthesis

Abstract The stereochemistry of the formation of natural rubber and trans-trans-farnesyl pyrophosphate in latex has been studied in vitro using [2−14C−(4R)−3H1] and [2−14C−(4S)−4−3H1]mevalonates as substrates. The proton eliminated from C-2 of isopentenyl pyrophosphate during the formation of farnesyl pyrophosphate in latex has the same steric position as that released in the liver system, and is epimeric with that eliminated during the biosynthesis of rubber. Complete stereospecificity is exhibited by the enzymes in the two cases. In rubber biosynthesis isoprene residues are incorporated directly in all-cis configuration without the intervention of trans structures.

scholarly journals Regulatory Potential of bHLH-Type Transcription Factors on the Road to Rubber Biosynthesis in Hevea brasiliensis

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 674
Author(s):  
Tomoko Yamaguchi ◽  
Yukio Kurihara ◽  
Yuko Makita ◽  
Emiko Okubo-Kurihara ◽  
Ami Kageyama ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Natural Rubber ◽  
Hevea Brasiliensis ◽  
Time Course ◽  
Molecular Mechanisms ◽  
Cultured Cells ◽  
Early Stage ◽  
Rubber Biosynthesis ◽  
On The Road

Natural rubber is the main component of latex obtained from laticifer cells of Hevea brasiliensis. For improving rubber yield, it is essential to understand the genetic molecular mechanisms responsible for laticifer differentiation and rubber biosynthesis. Jasmonate enhances both secondary laticifer differentiation and rubber biosynthesis. Here, we carried out time-course RNA-seq analysis in suspension-cultured cells treated with methyljasmonic acid (MeJA) to characterize the gene expression profile. Gene Ontology (GO) analysis showed that the term “cell differentiation” was enriched in upregulated genes at 24 h after treatment, but inversely, the term was enriched in downregulated genes at 5 days, indicating that MeJA could induce cell differentiation at an early stage of the response. Jasmonate signaling is activated by MYC2, a basic helix–loop–helix (bHLH)-type transcription factor (TF). The aim of this work was to find any links between transcriptomic changes after MeJA application and regulation by TFs. Using an in vitro binding assay, we traced candidate genes throughout the whole genome that were targeted by four bHLH TFs: Hb_MYC2-1, Hb_MYC2-2, Hb_bHLH1, and Hb_bHLH2. The latter two are highly expressed in laticifer cells. Their physical binding sites were found in the promoter regions of a variety of other TF genes, which are differentially expressed upon MeJA exposure, and rubber biogenesis-related genes including SRPP1 and REF3. These studies suggest the possibilities that Hb_MYC2-1 and Hb_MYC2-2 regulate cell differentiation and that Hb_bHLH1 and Hb_bHLH2 promote rubber biosynthesis. We expect that our findings will help to increase natural rubber yield through genetic control in the future.

UNRAVELING THE MYSTERY OF NATURAL RUBBER BIOSYNTHESIS. PART II: COMPOSITION AND GROWTH OF IN VITRO NATURAL RUBBER USING HIGH-RESOLUTION SIZE EXCLUSION CHROMATOGRAPHY

2014 ◽  
Vol 87 (3) ◽  
pp. 451-458 ◽  
Author(s):  
Cheng Ching K. Chiang ◽  
Balaka Barkakaty ◽  
Judit E. Puskas ◽  
Wenshuang Xie ◽  
Katrina Cornish ◽  
...  
Keyword(s):  
High Resolution ◽  
Natural Rubber ◽  
Size Exclusion Chromatography ◽  
Rubber Tree ◽  
Size Exclusion ◽  
Common Source ◽  
Rubber Biosynthesis ◽  
Flight Mass Spectrometry ◽  
Exclusion Chromatography

ABSTRACT The superior properties of natural rubber (cis-1,4-polyisoprene [NR]) are a function of its structure and composition, properties that still remain a mystery and that are irreplaceable by any synthetic rubber. NR from guayule (Parthenium argentatum) has been gaining special interest for its hypoallergenic properties while maintaining superior mechanical properties that are commonly associated with the Brazilian rubber tree (Hevea brasiliensis), the most common source of NR. Techniques exist to isolate washed rubber particles (WRPs) that contain enzymatically active rubber transferase, to study NR biosynthesis, and previous work on the in vitro NR growth in Hevea has demonstrated the presence of around 50 wt% of a low molecular weight ([MW], Mn <10 000 g/mol) fraction. Structural and compositional analyses of this low MW fraction in Hevea are challenging due to the high protein content. We discuss the analysis and composition of guayule latex and WRPs using high-resolution Size Exclusion Chromatography. We also discuss the composition of the soluble fraction of inactive guayule latex using matrix-assisted laser desorption ionization/time of flight mass spectrometry.

UNRAVELING THE MYSTERY OF NATURAL RUBBER BIOSYNTHESIS. PART I: INVESTIGATION OF THE COMPOSITION AND GROWTH OF IN VITRO NATURAL RUBBER USING HIGH RESOLUTION SIZE EXCLUSION CHROMATOGRAPHY

2011 ◽  
Vol 84 (2) ◽  
pp. 166-177 ◽  
Author(s):  
Chengching K. Chiang ◽  
Wenshuang Xie ◽  
Colleen McMahan ◽  
Judit E. Puskas
Keyword(s):  
High Resolution ◽  
Natural Rubber ◽  
Size Exclusion Chromatography ◽  
Weight Fraction ◽  
Size Exclusion ◽  
Gravimetric Analysis ◽  
In Vitro Synthesis ◽  
Rubber Biosynthesis ◽  
Exclusion Chromatography

Abstract Monitoring the growth of in vitro natural rubber was accomplished by high resolution size exclusion chromatography, SEC. Washed rubber particles isolated from H. brasiliensis latex, containing the rubber transferase enzyme, were used to catalyze the polymerization of synthetic isopentenyl pyrophosphate monomer in the presence of farnesyl pyrophosphate initiator. The high-resolution SEC was able to detect the formation of new rubber. Changes in the low molecular weight fraction were also detected. Gravimetric analysis revealed ∼30% mass gain after the in vitro synthesis. The overall gel content was found to be reduced, which further supported the formation of new rubber. This is the first report that utilizes high-resolution SEC to monitor the in vitro NR growth without the use of radiolabeling.

scholarly journals Biosynthesis of Natural Rubber: Current State and Perspectives

2018 ◽  
Vol 20 (1) ◽  
pp. 50 ◽  
Author(s):  
Xiao Men ◽  
Fan Wang ◽  
Guo-Qiang Chen ◽  
Hai-Bo Zhang ◽  
Mo Xian
Keyword(s):  
Natural Rubber ◽  
Growth Conditions ◽  
Genetically Engineered ◽  
Human Society ◽  
Rubber Biosynthesis ◽  
The Past ◽  
Current State ◽  
Natural Rubber Biosynthesis ◽  
Chain Polymerization

Natural rubber is a kind of indispensable biopolymers with great use and strategic importance in human society. However, its production relies almost exclusively on rubber-producing plants Hevea brasiliensis, which have high requirements for growth conditions, and the mechanism of natural rubber biosynthesis remains largely unknown. In the past two decades, details of the rubber chain polymerization and proteins involved in natural rubber biosynthesis have been investigated intensively. Meanwhile, omics and other advanced biotechnologies bring new insight into rubber production and development of new rubber-producing plants. This review summarizes the achievements of the past two decades in understanding the biosynthesis of natural rubber, especially the massive information obtained from the omics analyses. Possibilities of natural rubber biosynthesis in vitro or in genetically engineered microorganisms are also discussed.

scholarly journals Effects of Farnesyl Pyrophosphate Accumulation on Calvarial Osteoblast Differentiation

Endocrinology ◽  
2011 ◽  
Vol 152 (8) ◽  
pp. 3113-3122 ◽  
Author(s):  
Megan M. Weivoda ◽  
Raymond J. Hohl
Keyword(s):  
Bone Formation ◽  
Osteoblast Differentiation ◽  
Biosynthetic Pathway ◽  
Squalene Synthase ◽  
Farnesyl Pyrophosphate ◽  
Matrix Mineralization ◽  
Lower Serum Cholesterol ◽  
Calvarial Osteoblast ◽  
Isoprenoid Biosynthetic Pathway

Statins, drugs commonly used to lower serum cholesterol, have been shown to stimulate osteoblast differentiation and bone formation. Statins inhibit 3-hydroxy-3-methylglutaryl (HMG)-coenzyme A reductase (HMGCR), the first step of the isoprenoid biosynthetic pathway, leading to the depletion of the isoprenoids farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP). The effects of statins on bone have previously been attributed to the depletion of GGPP, because the addition of exogenous GGPP prevented statin-stimulated osteoblast differentiation in vitro. However, in a recent report, we demonstrated that the specific depletion of GGPP did not stimulate but, in fact, inhibited osteoblast differentiation. This led us to hypothesize that isoprenoids upstream of GGPP play a role in the regulation of osteoblast differentiation. We demonstrate here that the expression of HMGCR and FPP synthase decreased during primary calvarial osteoblast differentiation, correlating with decreased FPP and GGPP levels during differentiation. Zaragozic acid (ZGA) inhibits the isoprenoid biosynthetic pathway enzyme squalene synthase, leading to an accumulation of the squalene synthase substrate FPP. ZGA treatment of calvarial osteoblasts led to a significant increase in intracellular FPP and resulted in inhibition of osteoblast differentiation as measured by osteoblastic gene expression, alkaline phosphatase activity, and matrix mineralization. Simultaneous HMGCR inhibition prevented the accumulation of FPP and restored osteoblast differentiation. In contrast, specifically inhibiting GGPPS to lower the ZGA-induced increase in GGPP did not restore osteoblast differentiation. The specificity of HMGCR inhibition to restore osteoblast differentiation of ZGA-treated cultures through the reduction in isoprenoid accumulation was confirmed with the addition of exogenous mevalonate. Similar to ZGA treatment, exogenous FPP inhibited the mineralization of primary calvarial osteoblasts. Interestingly, the effects of FPP accumulation on osteoblasts were found to be independent of protein farnesylation. Our findings are the first to demonstrate that the accumulation of FPP impairs osteoblast differentiation and suggests that the depletion of this isoprenoid may be necessary for normal and statin-induced bone formation.

Initiation of rubber biosynthesis: In vitro comparisons of benzophenone-modified diphosphate analogues in three rubber-producing species

2008 ◽  
Vol 69 (14) ◽  
pp. 2539-2545 ◽  
Author(s):  
Wenshuang Xie ◽  
Colleen M. McMahan ◽  
Amanda J. DeGraw ◽  
Mark D. Distefano ◽  
Katrina Cornish ◽  
...  
Keyword(s):  
Rubber Biosynthesis
Sign in / Sign up

Export Citation Format

Share Document