Electron paramagnetic resonance investigation of different plant organs after gamma irradiation

et al. 2015

IJMS

AtTDX, a thioredoxin-like plant-specific protein present in Arabidospis is a thermo-stable and multi-functional enzyme. This enzyme is known to act as a thioredoxin and as a molecular chaperone depending upon its oligomeric status. The present study examines the effects of γ-irradiation on the structural and functional changes of AtTDX. Holdase chaperone activity of AtTDX was increased and reached a maximum at 10 kGy of γ-irradiation and declined subsequently in a dose-dependent manner, together with no effect on foldase chaperone activity. However, thioredoxin activity decreased gradually with increasing irradiation. Electrophoresis and size exclusion chromatography analysis showed that AtTDX had a tendency to form high molecular weight (HMW) complexes after γ-irradiation and γ-ray-induced HMW complexes were tightly associated with a holdase chaperone activity. The hydrophobicity of AtTDX increased with an increase in irradiation dose till 20 kGy and thereafter decreased further. Analysis of the secondary structures of AtTDX using far UV-circular dichroism spectra revealed that the irradiation remarkably increased the exposure of β-sheets and random coils with a dramatic decrease in α-helices and turn elements in a dose-dependent manner. The data of the present study suggest that γ-irradiation may be a useful tool for increasing holdase chaperone activity without adversely affecting foldase chaperone activity of thioredoxin-like proteins.

Section: Introductionmentioning

confidence: 99%

Enhancement of Chaperone Activity of Plant-Specific Thioredoxin through γ-Ray Mediated Conformational Change

Lee

Jung

et al. 2015

IJMS

“…ROS can also induce uncontrolled cellular proliferation, aging, and programmed cell death. Gamma radiolysis of water can produce various molecular species, free radicals, and ROS (Lee et al, 2012). Indeed, ionizing radiations such as gamma ray and electron beam can easily penetrate the orange peel and produce free radicals that may be useful in modification and breakdown of the limonene structure.…”

Section: Resultsmentioning

confidence: 99%

Degradation of limonene by gamma radiation for improving bioethanol production

Bai

Hong

J Korean Soc Appl Biol Chem

et al. 2014

Self Cite

Use of orange peel as a raw material for bioethanol production requires removal of its limonene content, which inhibits fermentation. Orange peel was pretreated using electron beam or gamma ray irradiation. Limonene content decreased in a dose-dependent manner, with approximately 60% reduction compared to the control after gamma irradiation at a dose of 800 kGy. However, electron beam irradiation did not demonstrate the same effectiveness. Therefore, gamma irradiation was deduced to be a promising pretreatment method for removing limonene from orange peel.

“…The chaperone activity of Pseudomonas putida peroxiredoxin (PpPrx) and P. aeruginosa peroxiredoxin (PaPrx) increased significantly (about 3–4-fold), but the peroxidase activity decreased with increasing radiation dose. Radiation of the protein causes the following chemical changes: fragmentation, cross-linking, aggregation, and oxidation by oxygen radicals that are generated in the radiolysis of water [ 19 – 23 ]. Although our earlier work suggested that the structural changes increased the chaperone activity and may be an important mechanism of functional switching in Prxs, gamma-ray and electron-beam irradiation decreased the peroxidase activity of these Prxs [ 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

Optimized enzymatic dual functions of PaPrx protein by proton irradiation

Journal of Radiation Research

Lee

Kim

et al. 2013

We investigated the effects of proton irradiation on the function and structure of the Pseudomonas aeruginosa peroxiredoxin (PaPrx). Polyacrylamide gel demonstrated that PaPrx proteins exposed to proton irradiation at several doses exhibited simultaneous formation of high molecular weight (HMW) complexes and fragmentation. Size-exclusion chromatography (SEC) analysis revealed that the number of fragments and very low molecular weight (LMW) structures increased as the proton irradiation dose increased. The peroxidase activity of irradiated PaPrx was preserved, and its chaperone activity was significantly increased by increasing the proton irradiation dose. The chaperone activity increased about 3–4 fold after 2.5 kGy proton irradiation, compared with that of non-irradiated PaPrx, and increased to almost the maximum activity after 10 kGy proton irradiation. We previously obtained functional switching in PaPrx proteins, by using gamma rays and electron beams as radiation sources, and found that the proteins exhibited increased chaperone activity but decreased peroxidase activity. Interestingly, in this study we newly found that proton irradiation could enhance both peroxidase and chaperone activities. Therefore, we can suggest proton irradiation as a novel protocol for conserved 2-Cys protein engineering.