Poly(ethylene terephthalate) (PET)-degrading bacterium Ideonella sakaiensis produces hydrolytic enzymes that convert PET, via mono(2-hydroxyethyl) terephthalate (MHET), into the monomeric compounds, terephthalic acid (TPA), and ethylene glycol (EG). Understanding PET metabolism is critical if this bacterium is to be engineered for bioremediation and biorecycling. TPA uptake and catabolism in I.
View Article and Find Full Text PDFExtracellular vesicles (EVs) are cell-derived lipid membrane capsules that can deliver functional molecules, such as nucleic acids, to target cells. Currently, the application of EVs is limited because of the difficulty of loading cargo into EVs. We constructed hybrid EVs by the fusion of liposomes and insect cell-derived EVs expressing recombinant programmed cell death 1 (PD-1) protein and baculoviral fusogenic glycoprotein gp64, and evaluated delivery of the model cargo molecule, Texas Red-labeled dextran (TR-Dex), into the cytosol.
View Article and Find Full Text PDFExtracellular vesicles (EVs) have potential biomedical applications, particularly as a means of transport for therapeutic agents. There is a need for rapid and efficient EV-liposome membrane fusion that maintains the integrity of hybrid EVs. We recently described Sf9 insect cell-derived EVs on which functional membrane proteins were presented using a baculovirus-expression system.
View Article and Find Full Text PDFPoly(ethylene terephthalate) (PET) is a widely used plastic in bottles and fibers; its waste products pollute the environment owing to its remarkable durability. Recently, Ideonella sakaiensis 201-F6 was isolated as a unique bacterium that can degrade and assimilate PET, thus paving the way for the bioremediation and bioconversion of PET waste. We found that this strain harbors a poly(hydroxyalkanoate) (PHA) synthesis gene cluster, which is highly homologous with that of Cupriavidus necator, an efficient PHA producer.
View Article and Find Full Text PDFPoly(ethylene terephthalate) (PET) is a commonly used synthetic plastic; however, its nonbiodegradability results in a large amount of waste accumulation that has a negative impact on the environment. Recently, a PET-degrading bacterium, Ideonella sakaiensis 201-F6 strain, was isolated, and the enzymes involved in PET digestion, PET hydrolase (PETase), and mono(2-hydroxyethyl) terephthalic acid (MHET) hydrolase (MHETase) were identified. Despite the great potentials of in bioremediation and biorecycling, approaches to studying this bacterium remain limited.
View Article and Find Full Text PDFFew reports have described the biological degradation or utilization of poly(ethylene terephthalate) (PET) to support microbial growth. We screened environmental samples from a PET bottle recycling site and identified the microbial consortium no. 46, which degraded amorphous PET at ambient temperature; thereafter, we isolated the resident Ideonella sakaiensis 201-F6 strain responsible for the degradation.
View Article and Find Full Text PDFExtracellular vesicles (EVs) facilitate intercellular communication by transporting functional molecules. The modification of EVs for clinical use as drug delivery systems is of considerable interest because of their biocompatibility and molecular transport ability. Programmed cell death ligand 1 (PD-L1) is an effective target molecule for drug delivery to cancer tissues and binds the single-transmembrane protein, Programmed cell death protein 1 (PD-1), an immune checkpoint that guards against autoimmunity.
View Article and Find Full Text PDFYang et al suggest that the use of low-crystallinity poly(ethylene terephthalate) (PET) exaggerates our results. However, the primary focus of our study was identifying an organism capable of the biological degradation and assimilation of PET, regardless of its crystallinity. We provide additional PET depolymerization data that further support several other lines of data showing PET assimilation by growing cells of Ideonella sakaiensis.
View Article and Find Full Text PDFA Gram-stain-negative, aerobic, non-spore-forming, rod-shaped bacterium, designed strain 201-F6T, was isolated from a microbial consortium that degrades poly(ethylene terephthalate) (PET) collected in Sakai city, Japan, and was characterized on the basis of a polyphasic taxonomic study. The cells were motile with a polar flagellum. The strain contained cytochrome oxidase and catalase.
View Article and Find Full Text PDFPoly(ethylene terephthalate) (PET) is used extensively worldwide in plastic products, and its accumulation in the environment has become a global concern. Because the ability to enzymatically degrade PET has been thought to be limited to a few fungal species, biodegradation is not yet a viable remediation or recycling strategy. By screening natural microbial communities exposed to PET in the environment, we isolated a novel bacterium, Ideonella sakaiensis 201-F6, that is able to use PET as its major energy and carbon source.
View Article and Find Full Text PDFA bacterial arylmalonate decarboxylase (AMDase) catalyzes asymmetric decarboxylation of unnatural arylmalonates to produce optically pure (R)-arylcarboxylates without the addition of cofactors. Previously, we designed an AMDase variant G74C/C188S that displays totally inverted enantioselectivity. However, the variant showed a 20,000-fold reduction in activity compared with the wild-type AMDase.
View Article and Find Full Text PDFThe analysis of the 6.8-Mbp draft genome sequence of the phenylmalonate-assimilating bacterium Bordetella bronchiseptica KU1201 identified 6,358 protein-coding sequences. This will give us an insight into the catabolic variability of this strain for aromatic compounds, along with the roles of arylmalonate decarboxylases in nature.
View Article and Find Full Text PDFKozakia baliensis belongs to the family Acetobacteraceae and was described for the first time in 2002. These acetic acid bacteria are able to produce acetic acid from various carbon sources and 2- and 5-keto-d-gluconate from glucose. The novel K.
View Article and Find Full Text PDFXylose, the major constituent of xylans, as well as the side chain sugars, such as arabinose, can be metabolized by engineered yeasts into ethanol. Therefore, xylan-degrading enzymes that efficiently hydrolyze xylans will add value to cellulases used in hydrolysis of plant cell wall polysaccharides for conversion to biofuels. Heterogeneous xylan is a complex substrate, and it requires multiple enzymes to release its constituent sugars.
View Article and Find Full Text PDFAMP phosphorylase (AMPpase), ribose-1,5-bisphosphate (R15P) isomerase, and type III ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) have been proposed to constitute a novel pathway involved in AMP metabolism in the Archaea. Here we performed a biochemical examination of AMPpase and R15P isomerase from Thermococcus kodakarensis. R15P isomerase was specific for the α-anomer of R15P and did not recognize other sugar compounds.
View Article and Find Full Text PDFRibose-1,5-bisphosphate isomerase (R15Pi) is a novel enzyme recently identified as a member of an AMP metabolic pathway in archaea. The enzyme converts d-ribose 1,5-bisphosphate into ribulose 1,5-bisphosphate, providing the substrate for archaeal ribulose-1,5-bisphosphate carboxylase/oxygenases. We here report the crystal structures of R15Pi from Thermococcus kodakarensis KOD1 (Tk-R15Pi) with and without its substrate or product.
View Article and Find Full Text PDFWe present characterization of PbFucA, a family 5 glycoside hydrolase (GH5) from Prevotella bryantii B(1)4. While GH5 members typically are xylanases, PbFucA shows no activity toward xylan polysaccharides. A screen against a panel of p-nitrophenol coupled sugars identifies PbFucA as a β-D-fucosidase.
View Article and Find Full Text PDFThe Calvin-Benson-Bassham cycle is responsible for carbon dioxide fixation in all plants, algae, and cyanobacteria. The enzyme that catalyzes the carbon dioxide-fixing reaction is ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Rubisco from a hyperthermophilic archaeon Thermococcus kodakarensis (Tk-Rubisco) belongs to the type III group, and shows high activity at high temperatures.
View Article and Find Full Text PDFFamily 43 glycoside hydrolases (GH43s) are known to exhibit various activities involved in hemicellulose hydrolysis. Thus, these enzymes contribute to efficient plant cell wall degradation, a topic of much interest for biofuel production. In this study, we characterized a unique GH43 protein from Fibrobacter succinogenes S85.
View Article and Find Full Text PDFThe hyperthermophilic archaeon Thermococcus kodakaraensis harbors a type III ribulose 1,5-bisphosphate carboxylase/oxygenase (Rbc(Tk)). It has previously been shown that Rbc(Tk) is capable of supporting photoautotrophic and photoheterotrophic growth in a mesophilic host cell, Rhodopseudomonas palustris Delta3, whose three native Rubisco genes had been disrupted. Here, we have examined the enzymatic properties of Rbc(Tk) at 25 degrees C and have constructed mutant proteins in order to enhance its performance in mesophilic host cells.
View Article and Find Full Text PDFThe hyperthermophilic archaeon, Thermococcus kodakaraensis KOD1 harbors a structurally novel, Type III Rubisco (Rbc(Tk)). In terms of protein engineering of Rubiscos, the enzyme may provide an alternative target to the conventional Type I and Type II enzymes. With a future aim to improve the catalytic properties of Rbc(Tk), here we examined whether or not the enzyme could support growth of a mesophilic organism dependent on CO2 fixation.
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