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Umar AW, Ahmad N, Xu M. Reviving Natural Rubber Synthesis via Native/Large Nanodiscs. Polymers (Basel) 2024; 16:1468. [PMID: 38891415 PMCID: PMC11174458 DOI: 10.3390/polym16111468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/28/2024] [Accepted: 05/17/2024] [Indexed: 06/21/2024] Open
Abstract
Natural rubber (NR) is utilized in more than 40,000 products, and the demand for NR is projected to reach $68.5 billion by 2026. The primary commercial source of NR is the latex of Hevea brasiliensis. NR is produced by the sequential cis-condensation of isopentenyl diphosphate (IPP) through a complex known as the rubber transferase (RTase) complex. This complex is associated with rubber particles, specialized organelles for NR synthesis. Despite numerous attempts to isolate, characterize, and study the RTase complex, definitive results have not yet been achieved. This review proposes an innovative approach to overcome this longstanding challenge. The suggested method involves isolating the RTase complex without using detergents, instead utilizing the native membrane lipids, referred to as "natural nanodiscs", and subsequently reconstituting the complex on liposomes. Additionally, we recommend the adaptation of large nanodiscs for the incorporation and reconstitution of the RTase complex, whether it is in vitro transcribed or present within the natural nanodiscs. These techniques show promise as a viable solution to the current obstacles. Based on our experimental experience and insights from published literature, we believe these refined methodologies can significantly enhance our understanding of the RTase complex and its role in in vitro NR synthesis.
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Affiliation(s)
- Abdul Wakeel Umar
- BNU-HKUST Laboratory of Green Innovation, Advanced Institute of Natural Sciences, Beijing Normal University at Zhuhai (BNUZ), Zhuhai 519087, China
| | - Naveed Ahmad
- Joint Center for Single Cell Biology, Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China;
| | - Ming Xu
- BNU-HKUST Laboratory of Green Innovation, Advanced Institute of Natural Sciences, Beijing Normal University at Zhuhai (BNUZ), Zhuhai 519087, China
- Guangdong-Hong Kong Joint Laboratory for Carbon Neutrality, Jiangmen Laboratory of Carbon Science and Technology, Jiangmen 529199, China
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Kwon M, Hodgins CL, Salama EM, Dias KR, Parikh A, Mackey AV, Catenza KF, Vederas JC, Ro DK. New insights into natural rubber biosynthesis from rubber-deficient lettuce mutants expressing goldenrod or guayule cis-prenyltransferase. THE NEW PHYTOLOGIST 2023; 239:1098-1111. [PMID: 37247337 DOI: 10.1111/nph.18994] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 04/23/2023] [Indexed: 05/31/2023]
Abstract
Lettuce produces natural rubber (NR) with an average Mw of > 1 million Da in laticifers, similar to NR from rubber trees. As lettuce is an annual, self-pollinating, and easily transformable plant, it is an excellent model for molecular genetic studies of NR biosynthesis. CRISPR/Cas9 mutagenesis was optimized using lettuce hairy roots, and NR-deficient lettuce was generated via bi-allelic mutations in cis-prenyltransferase (CPT). This is the first null mutant of NR deficiency in plants. In the CPT mutant, orthologous CPT counterparts from guayule (Parthenium argentatum) and goldenrod (Solidago canadensis) were expressed under a laticifer-specific promoter to examine how the average Mw of NR is affected. No developmental defects were observed in the NR-deficient mutants. The lettuce mutants expressing guayule and goldenrod CPT produced 1.8 and 14.5 times longer NR, respectively, than the plants of their origin. This suggests that, although goldenrod cannot synthesize a sufficiently lengthy NR, goldenrod CPT has the catalytic competence to produce high-quality NR in the cellular context of lettuce laticifers. Thus, CPT alone does not determine the length of NR. Other factors, such as substrate concentration, additional proteins, and/or the nature of protein complexes including CPT-binding proteins, influence CPT activity in determining NR length.
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Affiliation(s)
- Moonhyuk Kwon
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N 1N4, Canada
- Division of Applied Life Science (BK21 Four), ABC-RLRC, PMBBRC, Gyeongsang National University, Jinju, 52828, Korea
| | - Connor L Hodgins
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N 1N4, Canada
| | - Eman M Salama
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N 1N4, Canada
| | - Kayla R Dias
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N 1N4, Canada
| | - Aalap Parikh
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N 1N4, Canada
| | - Ashlyn V Mackey
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - Karizza F Catenza
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - John C Vederas
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - Dae-Kyun Ro
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N 1N4, Canada
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Nie Z, Kang G, Yan D, Qin H, Yang L, Zeng R. Downregulation of HbFPS1 affects rubber biosynthesis of Hevea brasiliensis suffering from tapping panel dryness. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 113:504-520. [PMID: 36524729 PMCID: PMC10107253 DOI: 10.1111/tpj.16063] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/01/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
Tapping panel dryness (TPD) is a century-old problem that has plagued the natural rubber production of Hevea brasiliensis. TPD may result from self-protective mechanisms of H. brasiliensis in response to stresses such as excessive hormone stimulation and mechanical wounding (bark tapping). It has been hypothesized that TPD impairs rubber biosynthesis; however, the underlying mechanisms remain poorly understood. In the present study, we firstly verified that TPD-affected rubber trees exhibited lower rubber biosynthesis activity and greater rubber molecular weight compared to healthy rubber trees. We then demonstrated that HbFPS1, a key gene of rubber biosynthesis, and its expression products were downregulated in the latex of TPD-affected rubber trees, as revealed by transcriptome sequencing and iTRAQ-based proteome analysis. We further discovered that the farnesyl diphosphate synthase HbFPS1 could be recruited to small rubber particles by HbSRPP1 through protein-protein interactions to catalyze farnesyl diphosphate (FPP) synthesis and facilitate rubber biosynthesis initiation. FPP content in the latex of TPD-affected rubber trees was significantly decreased with the downregulation of HbFPS1, ultimately resulting in abnormal development of rubber particles, decreased rubber biosynthesis activity, and increased rubber molecular weight. Upstream regulator assays indicated that a novel regulator, MYB2-like, may be an important regulator of downregulation of HbFPS1 in the latex of TPD-affected rubber trees. Our findings not only provide new directions for studying the molecular events involved in rubber biosynthesis and TPD syndrome and contribute to rubber management strategies, but also broaden our knowledge of plant isoprenoid metabolism and its regulatory networks.
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Affiliation(s)
- Zhiyi Nie
- Rubber Research Institute & Key Laboratory of Biology and Genetic Resources of Rubber treesMinistry of Agriculture and Rural Affairs of the People's Republic of China, Chinese Academy of Tropical Agricultural SciencesHaikou571101HainanChina
- Key Laboratory of Materials Engineering for High Performance Natural Rubber, Hainnan ProvinceChinese Academy of Tropical Agricultural SciencesHaikou571101HainanChina
| | - Guijuan Kang
- Rubber Research Institute & Key Laboratory of Biology and Genetic Resources of Rubber treesMinistry of Agriculture and Rural Affairs of the People's Republic of China, Chinese Academy of Tropical Agricultural SciencesHaikou571101HainanChina
- Key Laboratory of Materials Engineering for High Performance Natural Rubber, Hainnan ProvinceChinese Academy of Tropical Agricultural SciencesHaikou571101HainanChina
| | - Dong Yan
- Rubber Research Institute & Key Laboratory of Biology and Genetic Resources of Rubber treesMinistry of Agriculture and Rural Affairs of the People's Republic of China, Chinese Academy of Tropical Agricultural SciencesHaikou571101HainanChina
| | - Huaide Qin
- Rubber Research Institute & Key Laboratory of Biology and Genetic Resources of Rubber treesMinistry of Agriculture and Rural Affairs of the People's Republic of China, Chinese Academy of Tropical Agricultural SciencesHaikou571101HainanChina
- Key Laboratory of Materials Engineering for High Performance Natural Rubber, Hainnan ProvinceChinese Academy of Tropical Agricultural SciencesHaikou571101HainanChina
| | - Lifu Yang
- Institute of Scientific and Technical InformationChinese Academy of Tropical Agricultural SciencesHaikou571101HainanChina
| | - Rizhong Zeng
- Rubber Research Institute & Key Laboratory of Biology and Genetic Resources of Rubber treesMinistry of Agriculture and Rural Affairs of the People's Republic of China, Chinese Academy of Tropical Agricultural SciencesHaikou571101HainanChina
- Key Laboratory of Materials Engineering for High Performance Natural Rubber, Hainnan ProvinceChinese Academy of Tropical Agricultural SciencesHaikou571101HainanChina
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Dai L, Yang H, Zhao X, Wang L. Identification of cis conformation natural rubber and proteins in Ficus altissima Blume latex. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 167:376-384. [PMID: 34404008 DOI: 10.1016/j.plaphy.2021.08.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 08/05/2021] [Accepted: 08/09/2021] [Indexed: 06/13/2023]
Abstract
Ficus altissima Blume, a horticultural plant in tropical and warm subtropical regions, can produce natural rubber with comparable molecular weight to the Hevea brasiliensis rubber. The F. altissima latex has an acidic pH (about 4.89). The rubber particle size distribution is a unimodal profile, and the peak frequency is at a size of 4.5 μm. The natural rubber of F. altissima was determined to be a cis conformation via 13C NMR. The Mp (molecular weight of the peak maxima) of the deproteinized F. altissima rubber was 9.34 × 105 Da. LC-MS was used to identify the proteins of rubber particles and serum. The most abundant protein of the creamy rubber particle layer is an acid phosphatase, while the most abundant proteins of serum were an (R)-mandelonitrilelyase and a polygalacturonase inhibitor. Pharmaceutical proteins (ficins) or enzymes related to the biosynthesis of natural medicines (a cannabidiolic acid synthase and two lupeol synthase) were identified in F. altissima latex. The data of this study may be helpful for research on the functions of latex in latex-borne plants and the biosynthesis mechanism of natural rubber.
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Affiliation(s)
- Longjun Dai
- Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture and Rural Affairs, Haikou, Hainan, PR China; State Key Laboratory Incubation Base for Cultivation & Physiology of Tropical Crops, Haikou, Hainan, PR China; Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences (CATAS), Haikou, Hainan, PR China.
| | - Hong Yang
- Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture and Rural Affairs, Haikou, Hainan, PR China; State Key Laboratory Incubation Base for Cultivation & Physiology of Tropical Crops, Haikou, Hainan, PR China; Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences (CATAS), Haikou, Hainan, PR China.
| | - Xizhu Zhao
- Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture and Rural Affairs, Haikou, Hainan, PR China; State Key Laboratory Incubation Base for Cultivation & Physiology of Tropical Crops, Haikou, Hainan, PR China; Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences (CATAS), Haikou, Hainan, PR China.
| | - Lifeng Wang
- Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture and Rural Affairs, Haikou, Hainan, PR China; State Key Laboratory Incubation Base for Cultivation & Physiology of Tropical Crops, Haikou, Hainan, PR China; Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences (CATAS), Haikou, Hainan, PR China.
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Qu L, Li HL, Guo D, Wang Y, Zhu JH, Yin LY, Peng SQ. HbWRKY27, a group IIe WRKY transcription factor, positively regulates HbFPS1 expression in Hevea brasiliensis. Sci Rep 2020; 10:20639. [PMID: 33244131 PMCID: PMC7692525 DOI: 10.1038/s41598-020-77805-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 11/17/2020] [Indexed: 11/09/2022] Open
Abstract
Farnesyl pyrophosphate synthase (FPS) is a key enzyme that catalyzes the formation of farnesyl pyrophosphate, the main initiator for rubber chain initiation in Hevea brasiliensis Muell. Arg. The transcriptional regulatory mechanisms of the FPS gene still not well understood. Here, a WRKY transcription factor designated HbWRKY27 was obtained by screening the latex cDNA library applied the HbFPS1 promoter as bait. HbWRKY27 interacted with the HbFPS1 promoter was further identified by individual Y1H and EMSA assays. HbWRKY27 belongs to group IIe WRKY subfamily which contains a typical WRKY domain and C-X5-CX23-HXH motif. HbWRKY27 was localized to the nucleus. HbWRKY27 predominantly accumulated in latex. HbWRKY27 was up-regulated in latex by ethrel, salicylic acid, abscisic acid, and methyl jasmonate treatment. Transient expression of HbWRKY27 led to increasing the activity of the HbFPS1 promoter in tobacco plant, suggesting that HbWRKY27 positively regulates the HbFPS1 expression. Taken together, an upstream transcription factor of the key natural rubber biosynthesis gene HbFPS1 was identified and this study will provide novel transcriptional regulatory mechanisms of the FPS gene in Hevea brasiliensis.
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Affiliation(s)
- Long Qu
- School of Life and Pharmaceutical Sciences, Hainan University, Haikou, 570228, China
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, No.4 Xueyuan Road, Haikou, 571101, China
| | - Hui-Liang Li
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, No.4 Xueyuan Road, Haikou, 571101, China
| | - Dong Guo
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, No.4 Xueyuan Road, Haikou, 571101, China
| | - Ying Wang
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, No.4 Xueyuan Road, Haikou, 571101, China
| | - Jia-Hong Zhu
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, No.4 Xueyuan Road, Haikou, 571101, China
| | - Li-Yan Yin
- School of Life and Pharmaceutical Sciences, Hainan University, Haikou, 570228, China.
| | - Shi-Qing Peng
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, No.4 Xueyuan Road, Haikou, 571101, China.
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Azadi S, Bagheri H, Mohammad Parast B, Ghorbani-Marghashi M. Natural rubber identification and characterization in Euphorbia macroclada. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2020; 26:2047-2052. [PMID: 33088048 PMCID: PMC7548304 DOI: 10.1007/s12298-020-00880-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 07/07/2020] [Accepted: 09/01/2020] [Indexed: 05/29/2023]
Abstract
Natural rubber is one of the most important polymers produced by plants, which contains cis-1,4-polyisoprene, protein and fatty acids. It has unique properties compared to synthetic rubber and has many different uses in industry. Here, natural rubber of Euphorbia macroclada was characterized due to its abundance in arid areas. Isolation of rubber was done using both acetone and hexane solvents. FT-IR and NMR further characterized and confirmed the structure of rubber as cis-1,4 polyisoprene. GPC analyses showed a molecular weight of 8.180E+2 with polydispersity of 1.287. These data is useful for better understanding of latex composition in family of Euphorbiaceae.
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Affiliation(s)
- Somaye Azadi
- Department of Biotechnology, Faculty of Agriculture, Bu-Ali Sina University, Hamedan, Iran
| | - Hedayat Bagheri
- Department of Biotechnology, Faculty of Agriculture, Bu-Ali Sina University, Hamedan, Iran
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Yanchan Wei, Ding A, Jin L, Zhang H, Liao S. Quantitative Analysis of Abnormal Groups on Molecular Chain of Natural Rubber. POLYMER SCIENCE SERIES B 2019. [DOI: 10.1134/s1560090419070030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Cherian S, Ryu SB, Cornish K. Natural rubber biosynthesis in plants, the rubber transferase complex, and metabolic engineering progress and prospects. PLANT BIOTECHNOLOGY JOURNAL 2019; 17:2041-2061. [PMID: 31150158 PMCID: PMC6790360 DOI: 10.1111/pbi.13181] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 05/24/2019] [Accepted: 05/29/2019] [Indexed: 05/26/2023]
Abstract
Natural rubber (NR) is a nonfungible and valuable biopolymer, used to manufacture ~50 000 rubber products, including tires and medical gloves. Current production of NR is derived entirely from the para rubber tree (Hevea brasiliensis). The increasing demand for NR, coupled with limitations and vulnerability of H. brasiliensis production systems, has induced increasing interest among scientists and companies in potential alternative NR crops. Genetic/metabolic pathway engineering approaches, to generate NR-enriched genotypes of alternative NR plants, are of great importance. However, although our knowledge of rubber biochemistry has significantly advanced, our current understanding of NR biosynthesis, the biosynthetic machinery and the molecular mechanisms involved remains incomplete. Two spatially separated metabolic pathways provide precursors for NR biosynthesis in plants and their genes and enzymes/complexes are quite well understood. In contrast, understanding of the proteins and genes involved in the final step(s)-the synthesis of the high molecular weight rubber polymer itself-is only now beginning to emerge. In this review, we provide a critical evaluation of recent research developments in NR biosynthesis, in vitro reconstitution, and the genetic and metabolic pathway engineering advances intended to improve NR content in plants, including H. brasiliensis, two other prospective alternative rubber crops, namely the rubber dandelion and guayule, and model species, such as lettuce. We describe a new model of the rubber transferase complex, which integrates these developments. In addition, we highlight the current challenges in NR biosynthesis research and future perspectives on metabolic pathway engineering of NR to speed alternative rubber crop commercial development.
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Affiliation(s)
- Sam Cherian
- Plant Systems Engineering Research CentreKorea Research Institute of Bioscience and Biotechnology (KRIBB)Yuseong‐guDaejeonKorea
- Research & Development CenterDRB Holding Co. LTDBusanKorea
| | - Stephen Beungtae Ryu
- Plant Systems Engineering Research CentreKorea Research Institute of Bioscience and Biotechnology (KRIBB)Yuseong‐guDaejeonKorea
- Department of Biosystems and BioengineeringKRIBB School of BiotechnologyKorea University of Science and Technology (UST)DaejeonKorea
| | - Katrina Cornish
- Department of Horticulture and Crop ScienceThe Ohio State UniversityWoosterOHUSA
- Department of Food, Agricultural and Biological EngineeringThe Ohio State UniversityWoosterOHUSA
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Men X, Wang F, Chen GQ, Zhang HB, Xian M. Biosynthesis of Natural Rubber: Current State and Perspectives. Int J Mol Sci 2018; 20:E50. [PMID: 30583567 PMCID: PMC6337083 DOI: 10.3390/ijms20010050] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 12/17/2018] [Accepted: 12/19/2018] [Indexed: 12/12/2022] Open
Abstract
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.
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Affiliation(s)
- Xiao Men
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao 266101, China.
| | - Fan Wang
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao 266101, China.
- University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Guo-Qiang Chen
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao 266101, China.
| | - Hai-Bo Zhang
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao 266101, China.
| | - Mo Xian
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao 266101, China.
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Zhang X, Guo T, Xiang T, Dong Y, Zhang J, Zhang L. Quantitation of isoprenoids for natural rubber biosynthesis in natural rubber latex by liquid chromatography with tandem mass spectrometry. J Chromatogr A 2018; 1558:115-119. [PMID: 29773339 DOI: 10.1016/j.chroma.2018.05.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 03/01/2018] [Accepted: 05/03/2018] [Indexed: 12/30/2022]
Abstract
The natural rubber molecule is one of the end products of isoprenoids metabolism in the plant. Dimethylallyl diphosphate (DMAPP) and farnesyl pyrophosphate (FPP) are two typical isoprenoids which control the rate of biosynthesis and the molecular weight of natural rubber. A rapid, nonradioactive method for quantitation of DMAPP and FPP in natural rubber latex by liquid chromatography tandem with mass spectrometry (LC-MS/MS) was reported. DMAPP and FPP were determined in the multiple reaction monitoring mode(MRM)followed by separation with a silica-based C18 column. The external standard quantitative method was established, and the results showed limits of quantitation (LOQs) were 28 ng/ml and 33 ng/ml for DMAPP and FPP, respectively. The concentrations were detected 70-96 ng/ml and 242-375 ng/ml for these two isoprenoids in natural rubber latex. Recoveries of the method were in the range 81-93%. Daytime comparison experiments found that FPP had better stability than DMAPP.
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Affiliation(s)
- Xi Zhang
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, PR China; Engineering Research Center of Elastomer Materials Energy Conservation and Resources, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Tianyang Guo
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Tong Xiang
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, PR China; Engineering Research Center of Elastomer Materials Energy Conservation and Resources, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Yiyang Dong
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China.
| | - Jichuan Zhang
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, PR China; Engineering Research Center of Elastomer Materials Energy Conservation and Resources, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, PR China.
| | - Liqun Zhang
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, PR China; Engineering Research Center of Elastomer Materials Energy Conservation and Resources, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, PR China; Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China
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Amerik AY, Martirosyan YT, Gachok IV. Regulation of Natural Rubber Biosynthesis by Proteins Associated with Rubber Particles. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2018. [DOI: 10.1134/s106816201801003x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Laibach N, Post J, Twyman RM, Gronover CS, Prüfer D. The characteristics and potential applications of structural lipid droplet proteins in plants. J Biotechnol 2014; 201:15-27. [PMID: 25160916 DOI: 10.1016/j.jbiotec.2014.08.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 08/07/2014] [Accepted: 08/18/2014] [Indexed: 10/24/2022]
Abstract
Plant cytosolic lipid droplets are storage organelles that accumulate hydrophobic molecules. They are found in many tissues and their general structure includes an outer lipid monolayer with integral and associated proteins surrounding a hydrophobic core. Two distinct types can be distinguished, which we define here as oleosin-based lipid droplets (OLDs) and non-oleosin-based lipid droplets (NOLDs). OLDs are the best characterized lipid droplets in plants. They are primarily restricted to seeds and other germinative tissues, their surface is covered with oleosin-family proteins to maintain stability, they store triacylglycerols (TAGs) and they are used as a source of energy (and possibly signaling molecules) during the germination of seeds and pollen. Less is known about NOLDs. They are more abundant than OLDs and are distributed in many tissues, they accumulate not only TAGs but also other hydrophobic molecules such as natural rubber, and the structural proteins that stabilize them are unrelated to oleosins. In many species these proteins are members of the rubber elongation factor superfamily. NOLDs are not typically used for energy storage but instead accumulate hydrophobic compounds required for environmental interactions such as pathogen defense. There are many potential applications of NOLDs including the engineering of lipid production in plants and the generation of artificial oil bodies.
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Affiliation(s)
- Natalie Laibach
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Schlossplatz 8, 48143 Münster, Germany.
| | - Janina Post
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Schlossplatz 8, 48143 Münster, Germany.
| | | | - Christian Schulze Gronover
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Schlossplatz 8, 48143 Münster, Germany.
| | - Dirk Prüfer
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Schlossplatz 8, 48143 Münster, Germany; Westphalian Wilhelms-University of Münster, Institute of Plant Biology and Biotechnology, Schlossplatz 8, 48143 Münster, Germany.
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Praznik W, Löppert R, Huber A. Natural Polymer Resources: Isolation, Separation and Characterization. RENEWABLE RESOURCES FOR FUNCTIONAL POLYMERS AND BIOMATERIALS 2011. [DOI: 10.1039/9781849733519-00015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
This chapter describes various strategies and analytical techniques used for isolation, separation and characterization of natural polymers as the essential first step for their applications in food, feed and non-food products. It discusses different methods used for isolation and characterization of polysaccharides at the molecular and supramolecular levels. The discussion is exemplified by the detailed structural analysis of, among others, heteropolysaccharides like mucilage and fructans by permethylation, reductive cleavage and acetylation, followed by gas liquid chromatography. Data are also presented for supramolecular dimensions and molecular weights of poly-saccharides from various sources by different chromatographic methods combined with inline multiple detection systems (mass, light scattering, viscosity, fluorescence). The analysis and characterisation of plant and animal proteins are also briefly discussed.
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Affiliation(s)
- Werner Praznik
- Department of Chemistry University of Natural Resources & Life Science, Vienna Austria
| | - Renate Löppert
- Department of Chemistry University of Natural Resources & Life Science, Vienna Austria
| | - Anton Huber
- Institute of Chemistry (IFC) Karl-Franzens University of Graz (KFUG), Graz Austria
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Chiang CK, Xie W, McMahan C, Puskas JE. 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. RUBBER CHEMISTRY AND TECHNOLOGY 2011. [DOI: 10.5254/1.3570528] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
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.
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Affiliation(s)
| | | | | | - Judit E. Puskas
- 1Department Of Polymer Science, University Of Akron, Akron, OH
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Xie W, McMahan CM, Degraw AJ, Distefano MD, Cornish K, Whalen MC, Shintani DK. Initiation of rubber biosynthesis: In vitro comparisons of benzophenone-modified diphosphate analogues in three rubber-producing species. PHYTOCHEMISTRY 2008; 69:2539-2545. [PMID: 18799172 DOI: 10.1016/j.phytochem.2008.07.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2008] [Revised: 07/25/2008] [Accepted: 07/25/2008] [Indexed: 05/26/2023]
Abstract
Natural rubber, cis-1,4-polyisoprene, is a vital industrial material synthesized by plants via a side branch of the isoprenoid pathway by the enzyme rubber transferase. While the specific structure of this enzyme is not yet defined, based on activity it is probably a cis-prenyl transferase. Photoactive functionalized substrate analogues have been successfully used to identify isoprenoid-utilizing enzymes such as cis- and trans-prenyltransferases, and initiator binding of an allylic pyrophosphate molecule in rubber transferase has similar features to these systems. In this paper, a series of benzophenone-modified initiator analogues were shown to successfully initiate rubber biosynthesis in vitro in enzymatically-active washed rubber particles from Ficus elastica, Heveabrasiliensis and Parthenium argentatum. Rubber transferases from all three species initiated rubber biosynthesis most efficiently with farnesyl pyrophosphate. However, rubber transferase had a higher affinity for benzophenone geranyl pyrophosphate (Bz-GPP) and dimethylallyl pyrophosphate (Bz-DMAPP) analogues with ether-linkages than the corresponding GPP or DMAPP. In contrast, ester-linked Bz-DMAPP analogues were less efficient initiators than DMAPP. Thus, rubber biosynthesis depends on both the size and the structure of Bz-initiator molecules. Kinetic studies thereby inform selection of specific probes for covalent photolabeling of the initiator binding site of rubber transferase.
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Affiliation(s)
- Wenshuang Xie
- University of Nevada, Department of Biochemistry and Molecular Biology/MS200, Reno, NV 89557, United States
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Establishment of new crops for the production of natural rubber. Trends Biotechnol 2007; 25:522-9. [DOI: 10.1016/j.tibtech.2007.08.009] [Citation(s) in RCA: 212] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 07/19/2007] [Accepted: 08/09/2007] [Indexed: 11/20/2022]
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Bushman BS, Scholte AA, Cornish K, Scott DJ, Brichta JL, Vederas JC, Ochoa O, Michelmore RW, Shintani DK, Knapp SJ. Identification and comparison of natural rubber from two Lactuca species. PHYTOCHEMISTRY 2006; 67:2590-6. [PMID: 17055543 DOI: 10.1016/j.phytochem.2006.09.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Revised: 08/24/2006] [Accepted: 09/08/2006] [Indexed: 05/12/2023]
Abstract
Renewed interest in the identification of alternative sources of natural rubber to Hevea brasiliensis has focused on the Compositae family. In our search for Compositae models for rubber synthesis, we extracted latex from stems of two lettuce species: Lactuca serriola, prickly lettuce, and Lactuca sativa cv. Salinas, crisphead lettuce. Both species contained cis-1,4-polyisoprene rubber in the dichloromethane-soluble portions of their latex, and sesquiterpene lactones in their acetone-soluble portions. The rubber from both species and their progeny had molecular weights in excess of 1,000,000g/mol, and polydispersity values of 1.1. Rubber transferase activity was detected across a range of farnesyl diphosphate initiator concentrations, with decreased activity as initiator concentrations exceeded putative saturation. These results add lettuce to the short list of plant species that produce high molecular weight rubber in their latex. Due to the genomic and agronomic resources available in lettuce species, they provide the opportunity for further dissection of natural rubber biosynthesis in plants.
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Affiliation(s)
- Bradley S Bushman
- The Center for Applied Genetic Technologies, University of Georgia, 111 Riverbend Road, Athens, GA, USA
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Espy SC, Keasling JD, Castillón J, Cornish K. Initiator-independent and initiator-dependent rubber biosynthesis in Ficus elastica. Arch Biochem Biophys 2006; 448:13-22. [PMID: 16488387 DOI: 10.1016/j.abb.2006.01.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Revised: 01/06/2006] [Accepted: 01/14/2006] [Indexed: 11/27/2022]
Abstract
The rubber-producing tree, Ficus elastica (the Indian rubber tree), requires the same substrates for rubber production as other rubber-producing plants, such as Hevea brasiliensis (the Brazilian or Para rubber tree), the major source of commercial natural rubber in the world, and Parthenium argentatum (guayule), a widely studied alternative for natural rubber production currently under commercial development. Rubber biosynthesis can be studied, in vitro, using purified, enzymatically active rubber particles, an initiator such as FPP, IPP as the source of monomer, and a metal cofactor such as Mg2+. However, unlike H. brasiliensis and P. argentatum, we show that enzymatically active rubber particles purified from F. elastica are able to synthesize rubber, in vitro, in the absence of added initiator. In this paper, we characterize, for the first time, the kinetic differences between initiator-dependent rubber biosynthesis, and initiator-independent rubber biosynthesis, and the effect of cofactor concentration on both of these processes.
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Affiliation(s)
- Stephanie C Espy
- Department of Chemical Engineering, University of California, Berkeley, CA 94720, USA
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da Costa BMT, Keasling JD, Cornish K. Regulation of rubber biosynthetic rate and molecular weight in Hevea brasiliensis by metal cofactor. Biomacromolecules 2005; 6:279-89. [PMID: 15638531 DOI: 10.1021/bm049606w] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Metal ion cofactors are necessary for prenyltransferase enzymes. Magnesium and manganese can be used as metal ion cofactor by rubber transferase (a cis-prenyltransferase) associated with purified rubber particles. The rubber initiation rate, biosynthetic rate, and molecular weight produced in vitro from Hevea brasiliensis rubber transferase is regulated by metal ion concentration. In addition, varies significantly with [Mg(2+)]. decreases from 8000 +/- 600 microM at [Mg(2+)] = 4 mM to 68 +/- 10 microM at [Mg(2+)] = 8 mM and increases back to 970 +/- 70 microM at [Mg(2+)] = 30 mM. The highest affinity of rubber transferase for IPP.Mg occurred when [Mg(2+)] = A(max) (metal concentration that gives highest IPP incorporation rate). A metal ion is required for rubber biosynthesis, but an excess of metal ions interacts with the rubber transferase inhibiting its activity. The results suggest that H. brasiliensis could use [Mg(2+)] as a regulatory mechanism for rubber biosynthesis and molecular weight in vivo.
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Affiliation(s)
- Bernardo M T da Costa
- Department of Chemical Engineering, University of California, Berkeley, California 94720, USA
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Stubbe J, Tian J, He A, Sinskey AJ, Lawrence AG, Liu P. NONTEMPLATE-DEPENDENT POLYMERIZATION PROCESSES: Polyhydroxyalkanoate Synthases as a Paradigm. Annu Rev Biochem 2005; 74:433-80. [PMID: 15952894 DOI: 10.1146/annurev.biochem.74.082803.133013] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This review focuses on nontemplate-dependent polymerases that use water-soluble substrates and convert them into water-insoluble polymers that form granules or inclusions within the cell. The initial part of the review summarizes briefly the current knowledge of polymer formation catalyzed by starch and glycogen synthases, polyphosphate kinase (a polymerase), cyanophycin synthetases, and rubber synthases. Specifically, our current understanding of their mechanisms of initiation, elongation (including granule formation), termination, remodeling, and polymer reutilization will be presented. General underlying principles that govern these types of polymerization reactions will be enumerated as a paradigm for all nontemplate-dependent polymerizations. The bulk of the review then focuses on polyhydroxyalkanoate (PHA) synthases that generate polyoxoesters. These enzymes are of interest as they generate biodegradable polymers. Our current knowledge of PHA production and utilization in vitro and in vivo as well as the contribution of many proteins to these processes will be reviewed.
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Affiliation(s)
- Joanne Stubbe
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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Mau CJD, Garneau S, Scholte AA, Van Fleet JE, Vederas JC, Cornish K. Protein farnesyltransferase inhibitors interfere with farnesyl diphosphate binding by rubber transferase. ACTA ACUST UNITED AC 2003; 270:3939-45. [PMID: 14511375 DOI: 10.1046/j.1432-1033.2003.03775.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Rubber transferase, a cis-prenyltransferase, catalyzes the addition of thousands of isopentenyl diphosphate (IPP) molecules to an allylic diphosphate initiator, such as farnesyl diphosphate (FPP, 1), in the presence of a divalent metal cofactor. In an effort to characterize the catalytic site of rubber transferase, the effects of two types of protein farnesyltransferase inhibitors, several chaetomellic acid A analogs (2, 4-7) and alpha-hydroxyfarnesylphosphonic acid (3), on the ability of rubber transferase to add IPP to the allylic diphosphate initiator were determined. Both types of compounds inhibited the activity of rubber transferases from Hevea brasiliensis and Parthenium argentatum, but there were species-specific differences in the inhibition of rubber transferases by these compounds. Several shorter analogs of chaetomellic acid A did not inhibit rubber transferase activity, even though the analogs contained chemical features that are present in an elongating rubber molecule. These results indicate that the initiator-binding site in rubber transferase shares similar features to FPP binding sites in other enzymes.
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Affiliation(s)
- Christopher J D Mau
- USDA, Agricultural Research Service, Western Regional Research Center, Albany, CA 94710, USA
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Scott DJ, da Costa BMT, Espy SC, Keasling JD, Cornish K. Activation and inhibition of rubber transferases by metal cofactors and pyrophosphate substrates. PHYTOCHEMISTRY 2003; 64:123-134. [PMID: 12946411 DOI: 10.1016/s0031-9422(03)00266-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Metal cofactors are necessary for the activity of alkylation by prenyl transfer in enzyme-catalyzed reactions. Rubber transferase (RuT, a cis-prenyl transferase) associated with purified rubber particles from Hevea brasiliensis, Parthenium argentatum and Ficus elastica can use magnesium and manganese interchangably to achieve maximum velocity. We define the concentration of activator required for maximum velocity as [A](max). The [A](max)(Mg2+) in F. elastica (100 mM) is 10 times the [A](max)(Mg2+) for either H. brasiliensis (10 mM) or P. argentatum (8 mM). The [A](max)(Mn2+) in F. elastica (11 mM), H. brasiliensis (3.8 mM) and P. argentatum (6.8 mM) and the [A](max)(Mg2+) in H. brasiliensis (10 mM) and P. argentatum (8 mM) are similar. The differences in [A](max)(Mg2+) correlate with the actual endogenous Mg(2+) concentrations in the latex of living plants. Extremely low Mn(2+) levels in vivo indicate that Mg(2+) is the RuT cofactor in living H. brasiliensis and F. elastica trees. Kinetic analyses demonstrate that FPP-Mg(2+) and FPP-Mn(2+) are active substrates for rubber molecule initiation, although free FPP and metal cations, Mg(2+) and Mn(2+), can interact independently at the active site with the following relative dissociation constants K(d)(FPP) <K(d)(FPP-Metal) <K(d)(E-Metal). Similarly, IPP-Mg(2+) and IPP-Mn(2+) are active substrates for rubber molecule polymerization. Although metal cations can interact independently at the active site with the relative dissociation constant K(d)(IPP-Metal) <K(d)(E-Metal), unlike FPP, IPP alone does not interact independently. All three RuTs have similar characteristics-indeterminate sized products, high K(m)(IPP), high metal [A](max), metal cofactor requirements, and are membrane-bound enzymes.
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Affiliation(s)
- Deborah J Scott
- USDA-ARS, Western Regional Research Center, 800 Buchanan Street, Albany, CA 94710, USA
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Abstract
Biopolymers with true rubber properties are exceptionally rare in prokaryotic microorganisms. Only some polyhydroxyalkanoic acids are thermoplastic elastomers within a narrow temperature range that can be extended by crosslinking. Other polyhydroxyalkanoic acids are rigid and need specific thermal treatment during annealing to yield elastomeric materials. The most important elastomer is natural rubber (cis-1,4-polyisoprene). The rubber tree Hevea brasiliensis is so far the only relevant commercial source of this polymer, although many other plants are also capable of its synthesis. Recent advances in the analysis of isoprenoid and polyisoprene biosynthesis pathways have encouraged attempts to establish production of natural rubber in bacteria. Establishment of functional cis-1,4-polyisoprene biosynthesis pathways in bacteria depends firstly on the biosynthesis of isoprene moieties via the mevalonate or methylerythritol phosphate pathway and secondly on the polymerisation of isoprene moieties by a prenyltransferase yielding high-molecular-weight polyisoprenoids. The genes that encode prenyltransferases are as yet unknown and so the establishment of such a pathway and formation of rubber in recombinant bacteria will be a difficult task.
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Affiliation(s)
- Alexander Steinbüchel
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 3, D-48149 Münster, Germany.
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Cornish K. Similarities and differences in rubber biochemistry among plant species. PHYTOCHEMISTRY 2001; 57:1123-1134. [PMID: 11430985 DOI: 10.1016/s0031-9422(01)00097-8] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This report reviews aspects of the biochemical regulation of rubber yield and rubber quality in three contrasting rubber-producing species, Hevea brasiliensis, Parthenium argentatum and Ficus elastica. Although many similarities are revealed, considerable differences also exist in enzymatic mechanisms regulating biosynthetic rate and the molecular weight of the rubber biopolymers produced. In all three species, rubber molecule initiation, biosynthetic rate and molecular weight, in vitro, are dependent upon substrate concentration and the ratio of isopentenyl pyrophosphate (IPP, the elongation substrate, or monomer) and farnesyl pyrophosphate (FPP, an initiator), but these parameters are affected by intrinsic properties of the rubber transferases as well. All three rubber transferases are capable of producing a wide range of rubber molecular weight, depending upon substrate concentration, clearly demonstrating that the transferases are not the prime determinants of product size in vivo. However, despite these commonalities, considerable differences exist between the species with respect to cosubstrate effects, binding constants, effective concentration ranges, and the role of negative cooperativity in vitro. The P. argentatum rubber transferase appears to exert more control over the molecular weight it produces than the other two species and may, therefore, provide the best prospect for the source of genes for transformation of annual crop species. The kinetic data, from the three contrasting rubber-producing species, also were used to develop a model of the rubber transferase active site in which, in addition to separate IPP and allylic-PP binding sites, there exists a hydrophobic region that interacts with the linear portion of allylic-PP initiator proximal to the pyrophosphate. Substrate affinity increases until the active site is traversed and the rubber interior of the rubber particle is reached. The kinetic data suggest that the hydrophobic region in H. brasiliensis and F. elastica is about 1.8 nm long but only 1.3 nm in P. argentatum. The estimates are supported by measurements of the rubber particle monolayer membrane using electron paramagnetic resonance spectroscopy.
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Affiliation(s)
- K Cornish
- USDA-ARS, Western Regional Research Center, 800 Buchanan Street, Albany, CA 94710, USA.
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