Biology:Isoprene synthase
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| Isoprene synthase | |||||||||
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| Identifiers | |||||||||
| EC number | 4.2.3.27 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
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The enzyme isoprene synthase (EC 4.2.3.27) catalyzes the chemical reaction
- dimethylallyl pyrophosphate isoprene + diphosphate
This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on phosphates. The systematic name of this enzyme class is prenyl-diphosphate diphosphate-lyase (isoprene-forming). It is most commonly referred to as ISPS. The crystal structure of ISPS was the first of a hemiterpene synthase and was reported by the research group of David W. Christianson at the University of Pennsylvania.[1]
The substrate of isoprene synthase, dimethylallyl pyrophosphate, can be synthesised via two metabolic pathways: the methylerythritol phosphate pathway (MEP pathway) and the mevalonate pathway (MVA pathway). Plants comprise both the MEP pathway in the chloroplast and the MVA pathway in the cytoplasm, whereas some bacteria and archaea contain only one of the pathway to produce dimethylallyl pyrophosphate (DMAPP) and isopentenyl pyrophosphate (IPP), the substrates for terpene biosynthesis.
Isoprene synthases are found in terrestrial plants that emit isoprene. The best characterised and most commonly used isoprene synthases for biotechnology include the enzymes encoded by Eucalyptus globulus, Ipomea batatas, kudzu, Populus x canescens, Metrosideros polymorpha. Even though isoprene synthase encoding genes have only been found in plant genomes, there are bacteria that produce isoprene, e.g. from the Bacillus genus. Despite isoprene production, the enzyme responsible for the production of isoprene remains unknown in these species. It has been reported, that the MEP pathway enzyme 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (IspH), which catalyses the conversion of 4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP) to IPP and DMAPP, has a promiscuous activity and can produce isoprene.[2]
Enzyme kinetics, catalytic mechanism and physiological role
Compared to other monoterpene synthases, isoprene synthases usually have a lower substrate affinity, i.e. a higher KM value, which usually lies in the mM range, compared to other monoterpene synthases in the µM range.[3] This is caused by the need of dimethylallyl pyrophosphate, for the synthesis of essential terpenes and pigments. Therefore, isoprene synthase does not compete for substrates with other terpene synthases. Plants generally produce isoprene as a response to stress, such as elevated temperature, or cold stress. Isoprene synthase required a divalent metal ion for its catalytic activity, which is most commonly Mg2+.[1] However, in vitro experiments also showed high catalytic activity of Metrosideros polymorpha isoprene synthase with other metal ion cofactors, such as Mn2+, Zn2+, Cu2+, Ni2+ and Co2+.[4]
Use in biotechnology
Isoprene synthase encoding genes are used in biotechnology for the microbial isoprene production. This has only been reported in smaller scale academic research. Most bacteria do not produce isoprene, but with introduction of a plant derived isoprene synthase gene different species have been reported to emit isoprene. In the heterotrophic model organism Escherichia coli, where production rates of up to 2 g L−1 h−1 have been reported using the kudzu isoprene synthase.[5] Also photo-autotrophic organisms like cyanobacteria have been engineered to produce isoprene. Different isoprene synthases showed great differences in the production rates in the cyanobacterium Synechocystis sp. PCC6803, where the isoprene synthases from E. globulus and I. batatas showed the highest production rates,[6] reaching up to 150 mg L−1 h−1[7] with E. globulus isoprene synthase. Those isoprene synthases are known to have a lower KM and lower kcat value, which seem to be important for their role in biotechnology in photo-autotrophic hosts.
References
- ↑ 1.0 1.1 Köksal, Mustafa; Zimmer, Ina; Schnitzler, Jörg-Peter; Christianson, David W. (September 2010). "Structure of Isoprene Synthase Illuminates the Chemical Mechanism of Teragram Atmospheric Carbon Emission". Journal of Molecular Biology 402 (2): 363–373. doi:10.1016/j.jmb.2010.07.009. PMID 20624401. Bibcode: 2010JMBio.402..363K.
- ↑ Ge, Deyong; Xue, Yanfen; Ma, Yanhe (2016-05-11). "Two unexpected promiscuous activities of the iron–sulfur protein IspH in production of isoprene and isoamylene" (in en). Microbial Cell Factories 15 (1): 79. doi:10.1186/s12934-016-0476-9. ISSN 1475-2859. PMID 27169371.
- ↑ Schnitzer, JP; Zimmer, I; Bachl, A; Arend, M; Fromm, J; Fischbach, RJ (2005). "Biochemical properties of isoprene synthase in poplar (Populus × canescens)". Planta 222 (5): 777–786. doi:10.1007/s00425-005-0022-1. PMID 16052321. Bibcode: 2005Plant.222..777S. https://link.springer.com/article/10.1007/s00425-005-0022-1.
- ↑ Yeom, Soo-Jin; Kim, Moonjung; Kim, Seong Keun; Lee, Dae-Hee; Kwon, Kil Koang; Lee, Hyewon; Kim, Haseong; Kim, Dong-Myung et al. (2018-06-15). "Molecular and biochemical characterization of a novel isoprene synthase from Metrosideros polymorpha". BMC Plant Biology 18 (1): 118. doi:10.1186/s12870-018-1315-4. ISSN 1471-2229. PMID 29902970. Bibcode: 2018BMCPB..18..118Y.
- ↑ Whited, Gregory M.; Feher, Frank J.; Benko, David A.; Cervin, Marguerite A.; Chotani, Gopal K.; McAuliffe, Joseph C.; LaDuca, Richard J.; Ben-Shoshan, Eliahu A. et al. (2010-06-01). "TECHNOLOGY UPDATE: Development of a gas-phase bioprocess for isoprene-monomer production using metabolic pathway engineering" (in EN). Industrial Biotechnology 6 (3): 152–163. doi:10.1089/ind.2010.6.152. ISSN 1550-9087. https://journals.sagepub.com/action/showAbstract.
- ↑ Englund, Elias; Shabestary, Kiyan; Hudson, Elton P.; Lindberg, Pia (2018). "Systematic overexpression study to find target enzymes enhancing production of terpenes in Synechocystis PCC 6803, using isoprene as a model compound" (in en). Metabolic Engineering 49: 164–177. doi:10.1016/j.ymben.2018.07.004. PMID 30025762. https://linkinghub.elsevier.com/retrieve/pii/S1096717618301435.
- ↑ Janssen, Kim N.; Bolay, Paul; Tüllinghoff, Adrian; Toepel, Jörg; Spindler, Daniel; Bühler, Bruno; Lindberg, Pia (2026). "Engineering Cyanobacteria for High-Yield Photosynthetic Isoprene Production With Long-Term Phenotypic Stability" (in en). Plant Biotechnology Journal 24 (3): 1014–1030. doi:10.1111/pbi.70395. ISSN 1467-7652. PMID 41060093. Bibcode: 2026PBioJ..24.1014J.
Further reading
- "Enzymatic Synthesis of Isoprene from Dimethylallyl Diphosphate in Aspen Leaf Extracts". Plant Physiology 97 (4): 1588–1591. 1991. doi:10.1104/pp.97.4.1588. PMID 16668590.
- "Characterization of aspen isoprene synthase, an enzyme responsible for leaf isoprene emission to the atmosphere". Journal of Biological Chemistry 270 (22): 13010–6. 1995. doi:10.1074/jbc.270.22.13010. PMID 7768893.
- "Light-Dependent Isoprene Emission (Characterization of a Thylakoid-Bound Isoprene Synthase in Salix discolor Chloroplasts)". Plant Physiology 112 (1): 171–182. 1996. doi:10.1104/pp.112.1.171. PMID 12226383. Bibcode: 1996PlanP.112..171W.
- "Characterization of an Isoprene Synthase from Leaves of Quercus petraea (Mattuschka) Liebl.". Botanica Acta 109 (3): 216–221. 1996. doi:10.1111/j.1438-8677.1996.tb00566.x. Bibcode: 1996BotAc.109..216S.
- "First isolation of an isoprene synthase gene from poplar and successful expression of the gene in Escherichia coli". Planta 213 (3): 483–7. 2001. doi:10.1007/s004250100557. PMID 11506373. Bibcode: 2001Plant.213..483M.
- "Isoprene synthase activity parallels fluctuations of isoprene release during growth of Bacillus subtilis". Biochemical and Biophysical Research Communications 294 (1): 71–5. 2002. doi:10.1016/S0006-291X(02)00435-7. PMID 12054742. Bibcode: 2002BBRC..294...71S.
- "Gene expression and characterization of isoprene synthase from Populus alba". FEBS Letters 579 (11): 2514–8. 2005. doi:10.1016/j.febslet.2005.03.066. PMID 15848197. Bibcode: 2005FEBSL.579.2514S.
- "Biochemical properties of isoprene synthase in poplar (Populus x canescens)". Planta 222 (5): 777–86. 2005. doi:10.1007/s00425-005-0022-1. PMID 16052321. Bibcode: 2005Plant.222..777S.
- "Isoprene synthesis protects transgenic tobacco plants from oxidative stress". Plant, Cell & Environment 32 (5): 520–31. 2009. doi:10.1111/j.1365-3040.2009.01946.x. PMID 19183288. Bibcode: 2009PCEnv..32..520V.
- "Genetic structure and regulation of isoprene synthase in Poplar (Populus spp.)". Plant Molecular Biology 73 (4–5): 547–58. 2010. doi:10.1007/s11103-010-9642-3. PMID 20467886. Bibcode: 2010PMolB..73..547V.
- "Isoprene synthesis in plants – lessons from a transgenic tobacco model". Plant, Cell & Environment 34 (6): 1043–53. 2011. doi:10.1111/j.1365-3040.2011.02303.x. PMID 21388420. Bibcode: 2011PCEnv..34.1043V.
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