358-72-5Relevant articles and documents
Hydrogen exchange during the enzyme-catalyzed isomerization of isopentenyl diphosphate and dimethylallyl diphosphate
Street, Ian P.,Christensen, Dale J.,Poulter, C. Dale
, p. 8577 - 8578 (1990)
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Bioorganometallic mechanism of action, and inhibition, of IspH
Wang, Weixue,Wang, Ke,Liu, Yi-Liang,No, Joo-Hwan,Li, Jikun,Nilges, Mark J.,Oldfield, Eric
, p. 4522 - 4527 (2010)
We have investigated the mechanism of action of Aquifex aeolicus IspH [E-4-hydroxy-3-methyl-but-2-enyl diphosphate (HMBPP) reductase], together with its inhibition, using a combination of site-directed mutagenesis (K M;Vmax), EPR and 1H, 2H, 13C, 31P, and 57Fe-electron-nuclear double resonance (ENDOR) spectroscopy. On addition of HMBPP to an (unreactive) E126A IspH mutant, a reaction intermediate forms that has a very similar EPR spectrum to those seen previously with the HMBPP parent molecules, ethylene and allyl alcohol, bound to a nitrogenase FeMo cofactor. The EPR spectrum is broadened on 57Fe labeling and there is no evidence for the formation of allyl radicals. When combined with ENDOR spectroscopy, the results indicate formation of an organometallic species with HMBPP, a π?σ metallacycle or η2-alkenyl complex. The complex is poised to interact with H+ from E126 (and H124) in reduced wt IspH, resulting in loss of water and formation of an η1-allyl complex. After reduction, this forms an η3-allyl π-complex (i.e. containing an allyl anion) that on protonation (at C2 or C4) results in product formation. We find that alkyne diphosphates (such as propargyl diphosphate) are potent IspH inhibitors and likewise form metallacycle complexes, as evidenced by 1H, 2H, and 13C ENDOR, where hyperfine couplings of approximately 6 MHz for 13C and 10 MHz for 1H, are observed. Overall, the results are of broad general interest because they provide new insights into IspH catalysis and inhibition, involving organometallic species, and may be applicable to other Fe4S 4-containing proteins, such as IspG.
Scalable Biosynthesis of the Seaweed Neurochemical, Kainic Acid
Chekan, Jonathan R.,McKinnie, Shaun M. K.,Moore, Malia L.,Poplawski, Shane G.,Michael, Todd P.,Moore, Bradley S.
, p. 8454 - 8457 (2019)
Kainic acid, the flagship member of the kainoid family of natural neurochemicals, is a widely used neuropharmacological agent that helped unravel the key role of ionotropic glutamate receptors, including the kainate receptor, in the central nervous system. Worldwide shortages of this seaweed natural product in the year 2000 prompted numerous chemical syntheses, including scalable preparations with as few as six-steps. Herein we report the discovery and characterization of the concise two-enzyme biosynthetic pathway to kainic acid from l-glutamic acid and dimethylallyl pyrophosphate in red macroalgae and show that the biosynthetic genes are co-clustered in genomes of Digenea simplex and Palmaria palmata. Moreover, we applied a key biosynthetic α-ketoglutarate-dependent dioxygenase enzyme in a biotransformation methodology to efficiently construct kainic acid on the gram scale. This study establishes both the feasibility of mining seaweed genomes for their biotechnological prowess.
Probing the Substrate Promiscuity of Isopentenyl Phosphate Kinase as a Platform for Hemiterpene Analogue Production
Lund, Sean,Courtney, Taylor,Williams, Gavin J.
, p. 2217 - 2221 (2019/08/02)
Isoprenoids are a large class of natural products with wide-ranging applications. Synthetic biology approaches to the manufacture of isoprenoids and their new-to-nature derivatives are limited due to the provision in nature of just two hemiterpene buildin
IspH-RPS1 and IspH-UbiA: rosetta stone proteins
Rao, Guodong,O'Dowd, Bing,Li, Jikun,Wang, Ke,Oldfield, Eric
, p. 6813 - 6822 (2015/11/24)
The protein IspH, (E)-1-hydroxy-2-methyl-but-2-enyl 4-diphosphate (HMPPP) reductase, is an essential 4Fe-4S cluster-containing protein in the methylerythritol phosphate pathway for isoprenoid biosynthesis. Using a sequence similarity network we found that there are >400 IspH proteins that are about twice as large as most of the IspHs studied to date since their IspH domains are fused to either the ribosomal protein S1 (RPS1), or to a UbiA (4-hydroxybenzoate octaprenyltransferase)-like protein. Many of the IspH-RPS1 proteins are present in anaerobes found in the human gut and some, such as Clostridium botulinum, C. tetani and Fusobacterium nucleatum, are pathogens. The IspH-UbiAs are all found in sulfate-reducing anaerobes. The IspH domains in IspH-RPS1 are fused to 4 and in a few cases 6 tandem repeats in RPS1 that, in most organisms, bind to mRNA or form part of the bacterial ribosome. Mutants in which the four RPS1 domains were sequentially eliminated had similar IspH activity as wild-type protein, indicating they are not essential for IspH catalysis. Overall, the results are of interest since they represent the first isolation of a catalytically active IspH-RPS1, as well as the identification of IspH-UbiA hybrids, two Rosetta stone proteins that are likely to be functionally related - IspH producing the isoprenoids required for a UbiA-like prenyltransferase; the IspH-RPS1 hybrids, perhaps, being involved in the stringent response or as Fe/O2 sensors.
