title: Optimized enzymatic dual functions of PaPrx protein by proton irradiation.
abstract: 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.
authors.affiliation: Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185, Republic of Korea.
authors.forename: Chul-Hong
authors.initials: CH
authors.lastname: Park
authors.forename: Seung Sik
authors.initials: SS
authors.lastname: Lee
authors.forename: Kye Ryung
authors.initials: KR
authors.lastname: Kim
authors.forename: Myung Hwan
authors.initials: MH
authors.lastname: Jung
authors.forename: Sang Yeol
authors.initials: SY
authors.lastname: Lee
authors.forename: Eun Ju
authors.initials: EJ
authors.lastname: Cho
authors.forename: Sudhir
authors.initials: S
authors.lastname: Singh
authors.forename: Byung Yeoup
authors.initials: BY
authors.lastname: Chung
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure*; D004307:Dose-Response Relationship, Radiation; D004789:Enzyme Activation / Q000187:drug effects; D008968:Molecular Conformation / Q000528:radiation effects; D054464:Peroxiredoxins / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure*; D011522:Protons; D011829:Radiation Dosage; D013379:Substrate Specificity / Q000528:radiation effects
chemical_list: D001426:Bacterial Proteins; D011522:Protons; D054464:Peroxiredoxins
keywords: chaperone; peroxidase; peroxiredoxin; proton irradiation