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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Pseudomonas aeruginosa Dps (PA0962) Functions in H 2 O 2 Mediated Oxidative Stress Defense and Exhibits In Vitro DNA Cleaving Activity

We report the structural, biochemical, and functional characterization of the product of gene PA0962 from Pseudomonas aeruginosa PAO1. The protein, termed Pa Dps, adopts the Dps subunit fold and oligomerizes into a nearly spherical 12-mer quaternary structure at pH 6.0 or in the presence of divalent cations at neutral pH and above. The 12-Mer Pa Dps contains two di-iron centers at the interface of each subunit dimer, coordinated by conserved His, Glu, and Asp residues. In vitro, the di-iron centers catalyze the oxidation of Fe 2+ utilizing H 2 O 2 (not O 2 ) as an oxidant, suggesting Pa Dps functions to aid P. aeruginosa to survive H 2 O 2 -mediated oxidative stress. In agreement, a P. aeruginosa Δdps mutant is significantly more susceptible to H 2 O 2 than the parent strain. The Pa Dps structure harbors a novel network of Tyr residues at the interface of each subunit dimer between the two di-iron centers, which captures radicals generated during Fe 2+ oxidation at the ferroxidase centers and forms di-tyrosine linkages, thus effectively trapping the radicals within the Dps shell. Surprisingly, incubating Pa Dps and DNA revealed unprecedented DNA cleaving activity that is independent of H 2 O 2 or O 2 but requires divalent cations and 12-mer Pa Dps.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Simultaneous Separation of Protactinium-230 and Uranium-230 Isotopes from a Proton-Irradiated Thorium Matrix

The use of radioisotopes in cancer therapy is becoming increasingly important. As a potential candidate for targeted alpha therapy, 230 U (t 1/2 = 20.8 d), the decay daughter of 230 Pa (t 1/2 = 17.4 d) is currently being investigated for cancer treatment. For radioisotopes to be used in biomedicine, they must be radiochemically pure and free from carrier interference. This can be challenging given their short half-life. Thus, in this study, radiological separation methods for harvesting isotopes for use in biomedicine must be simple, fast, and capable of obtaining the required purity levels. Herein, we demonstrate a new rapid method for the separation of 230 U and 230 Pa from a proton-irradiated 232 Th metal target and from coproduced fission products with high recovery and purity. A dual-column approach was used, in which the first column was an anion exchange (AX) column and the second column was a DGA column. The MP-1 AX resin was used for the primary separation of the three major components (U, Pa, and Th, as well as fission products), and the DGA column was used for further purification of the separated 230 U. The method is simple and allows for straightforward separation of U, Pa, Th, and fission products; also, the entire process from target dissolution to shipment of 230 U could be completed in 3 days with an overall 230 U recovery yield of 96 ± 3%. Additionally, separated 230 Pa fractions can be used to harvest ingrown 230 U after initial separation.

DGA resin↗
DOE OSTI2020

Materials Data on PaGaCu2 by Materials Project

PaCu2Ga is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pa is bonded in a body-centered cubic geometry to eight equivalent Cu and six equivalent Ga atoms. All Pa–Cu bond lengths are 2.82 Å. All Pa–Ga bond lengths are 3.25 Å. Cu is bonded in a body-centered cubic geometry to four equivalent Pa and four equivalent Ga atoms. All Cu–Ga bond lengths are 2.82 Å. Ga is bonded in a distorted body-centered cubic geometry to six equivalent Pa and eight equivalent Cu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PaGaFe2 by Materials Project

PaFe2Ga is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pa is bonded in a distorted body-centered cubic geometry to eight equivalent Fe and six equivalent Ga atoms. All Pa–Fe bond lengths are 2.71 Å. All Pa–Ga bond lengths are 3.13 Å. Fe is bonded in a distorted body-centered cubic geometry to four equivalent Pa and four equivalent Ga atoms. All Fe–Ga bond lengths are 2.71 Å. Ga is bonded in a 8-coordinate geometry to six equivalent Pa and eight equivalent Fe atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PaGaNi2 by Materials Project

PaNi2Ga is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pa is bonded in a body-centered cubic geometry to eight equivalent Ni and six equivalent Ga atoms. All Pa–Ni bond lengths are 2.76 Å. All Pa–Ga bond lengths are 3.18 Å. Ni is bonded in a body-centered cubic geometry to four equivalent Pa and four equivalent Ga atoms. All Ni–Ga bond lengths are 2.76 Å. Ga is bonded in a distorted body-centered cubic geometry to six equivalent Pa and eight equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PaNi2Sb by Materials Project

PaNi2Sb is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pa is bonded in a distorted body-centered cubic geometry to eight equivalent Ni and six equivalent Sb atoms. All Pa–Ni bond lengths are 2.83 Å. All Pa–Sb bond lengths are 3.27 Å. Ni is bonded in a body-centered cubic geometry to four equivalent Pa and four equivalent Sb atoms. All Ni–Sb bond lengths are 2.83 Å. Sb is bonded in a distorted body-centered cubic geometry to six equivalent Pa and eight equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PaNi2Sn by Materials Project

PaNi2Sn is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pa is bonded in a distorted body-centered cubic geometry to eight equivalent Ni and six equivalent Sn atoms. All Pa–Ni bond lengths are 2.82 Å. All Pa–Sn bond lengths are 3.25 Å. Ni is bonded in a body-centered cubic geometry to four equivalent Pa and four equivalent Sn atoms. All Ni–Sn bond lengths are 2.82 Å. Sn is bonded in a 8-coordinate geometry to six equivalent Pa and eight equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PaPbAu2 by Materials Project

PaAu2Pb is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pa is bonded in a body-centered cubic geometry to eight equivalent Au and six equivalent Pb atoms. All Pa–Au bond lengths are 3.11 Å. All Pa–Pb bond lengths are 3.59 Å. Au is bonded in a body-centered cubic geometry to four equivalent Pa and four equivalent Pb atoms. All Au–Pb bond lengths are 3.11 Å. Pb is bonded in a distorted body-centered cubic geometry to six equivalent Pa and eight equivalent Au atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PaNi3 by Materials Project

PaNi3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Pa is bonded to twelve Ni atoms to form PaNi12 cuboctahedra that share corners with six equivalent PaNi12 cuboctahedra, corners with twelve NiPa4Ni8 cuboctahedra, edges with eighteen NiPa4Ni8 cuboctahedra, faces with eight equivalent PaNi12 cuboctahedra, and faces with twelve NiPa4Ni8 cuboctahedra. There are six shorter (2.64 Å) and six longer (2.84 Å) Pa–Ni bond lengths. There are three inequivalent Ni sites. In the first Ni site, Ni is bonded to four equivalent Pa and eight Ni atoms to form distorted NiPa4Ni8 cuboctahedra that share corners with four equivalent PaNi12 cuboctahedra, corners with fourteen NiPa4Ni8 cuboctahedra, edges with six equivalent PaNi12 cuboctahedra, edges with twelve NiPa4Ni8 cuboctahedra, faces with four equivalent PaNi12 cuboctahedra, and faces with sixteen NiPa4Ni8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.52–2.77 Å. In the second Ni site, Ni is bonded to four equivalent Pa and eight Ni atoms to form distorted NiPa4Ni8 cuboctahedra that share corners with four equivalent PaNi12 cuboctahedra, corners with fourteen NiPa4Ni8 cuboctahedra, edges with six equivalent PaNi12 cuboctahedra, edges with twelve NiPa4Ni8 cuboctahedra, faces with four equivalent PaNi12 cuboctahedra, and faces with sixteen NiPa4Ni8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.52–2.77 Å. In the third Ni site, Ni is bonded to four equivalent Pa and eight Ni atoms to form distorted NiPa4Ni8 cuboctahedra that share corners with four equivalent PaNi12 cuboctahedra, corners with fourteen NiPa4Ni8 cuboctahedra, edges with six equivalent PaNi12 cuboctahedra, edges with twelve NiPa4Ni8 cuboctahedra, faces with four equivalent PaNi12 cuboctahedra, and faces with sixteen NiPa4Ni8 cuboctahedra. Both Ni–Ni bond lengths are 2.77 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PaCu2Sn by Materials Project

PaCu2Sn is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pa is bonded in a distorted body-centered cubic geometry to eight equivalent Cu and six equivalent Sn atoms. All Pa–Cu bond lengths are 2.90 Å. All Pa–Sn bond lengths are 3.34 Å. Cu is bonded in a body-centered cubic geometry to four equivalent Pa and four equivalent Sn atoms. All Cu–Sn bond lengths are 2.90 Å. Sn is bonded in a 8-coordinate geometry to six equivalent Pa and eight equivalent Cu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pa2SbTe by Materials Project

Pa2SbTe is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pa is bonded in a body-centered cubic geometry to four equivalent Sb and four equivalent Te atoms. All Pa–Sb bond lengths are 3.22 Å. All Pa–Te bond lengths are 3.22 Å. Sb is bonded in a body-centered cubic geometry to eight equivalent Pa atoms. Te is bonded in a body-centered cubic geometry to eight equivalent Pa atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PaNi2Ge by Materials Project

PaNi2Ge is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pa is bonded in a distorted body-centered cubic geometry to eight equivalent Ni and six equivalent Ge atoms. All Pa–Ni bond lengths are 2.76 Å. All Pa–Ge bond lengths are 3.19 Å. Ni is bonded in a body-centered cubic geometry to four equivalent Pa and four equivalent Ge atoms. All Ni–Ge bond lengths are 2.76 Å. Ge is bonded in a distorted body-centered cubic geometry to six equivalent Pa and eight equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg3Pa by Materials Project

Mg3Pa is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. there are two inequivalent Mg sites. In the first Mg site, Mg is bonded in a body-centered cubic geometry to four equivalent Mg and four equivalent Pa atoms. All Mg–Mg bond lengths are 3.15 Å. All Mg–Pa bond lengths are 3.15 Å. In the second Mg site, Mg is bonded in a 8-coordinate geometry to eight equivalent Mg and six equivalent Pa atoms. All Mg–Pa bond lengths are 3.63 Å. Pa is bonded in a distorted body-centered cubic geometry to fourteen Mg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PaMn2Ga by Materials Project

PaMn2Ga is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pa is bonded in a distorted body-centered cubic geometry to eight equivalent Mn and six equivalent Ga atoms. All Pa–Mn bond lengths are 2.74 Å. All Pa–Ga bond lengths are 3.16 Å. Mn is bonded in a body-centered cubic geometry to four equivalent Pa and four equivalent Ga atoms. All Mn–Ga bond lengths are 2.74 Å. Ga is bonded in a distorted body-centered cubic geometry to six equivalent Pa and eight equivalent Mn atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PaTe2Pd by Materials Project

PaPdTe2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pa is bonded in a distorted body-centered cubic geometry to six equivalent Pd and eight equivalent Te atoms. All Pa–Pd bond lengths are 3.65 Å. All Pa–Te bond lengths are 3.16 Å. Pd is bonded in a 8-coordinate geometry to six equivalent Pa and eight equivalent Te atoms. All Pd–Te bond lengths are 3.16 Å. Te is bonded in a body-centered cubic geometry to four equivalent Pa and four equivalent Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pa2BiTe by Materials Project

Pa2BiTe is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pa is bonded in a body-centered cubic geometry to four equivalent Bi and four equivalent Te atoms. All Pa–Bi bond lengths are 3.26 Å. All Pa–Te bond lengths are 3.26 Å. Bi is bonded in a body-centered cubic geometry to eight equivalent Pa atoms. Te is bonded in a body-centered cubic geometry to eight equivalent Pa atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr3Pa by Materials Project

Sr3Pa is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. there are two inequivalent Sr sites. In the first Sr site, Sr is bonded to four equivalent Sr and four equivalent Pa atoms to form a mixture of distorted edge, face, and corner-sharing SrSr4Pa4 tetrahedra. All Sr–Sr bond lengths are 3.88 Å. All Sr–Pa bond lengths are 3.88 Å. In the second Sr site, Sr is bonded in a 8-coordinate geometry to eight equivalent Sr and six equivalent Pa atoms. All Sr–Pa bond lengths are 4.48 Å. Pa is bonded in a distorted body-centered cubic geometry to fourteen Sr atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg3Pa by Materials Project

Mg3Pa is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Mg sites. In the first Mg site, Mg is bonded to eight Mg and four equivalent Pa atoms to form distorted MgMg8Pa4 cuboctahedra that share corners with four equivalent PaMg12 cuboctahedra, corners with fourteen MgMg8Pa4 cuboctahedra, edges with six equivalent PaMg12 cuboctahedra, edges with twelve MgMg8Pa4 cuboctahedra, faces with four equivalent PaMg12 cuboctahedra, and faces with sixteen MgMg8Pa4 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.19–3.37 Å. There are two shorter (3.23 Å) and two longer (3.31 Å) Mg–Pa bond lengths. In the second Mg site, Mg is bonded to eight equivalent Mg and four equivalent Pa atoms to form distorted MgMg8Pa4 cuboctahedra that share corners with four equivalent PaMg12 cuboctahedra, corners with fourteen MgMg8Pa4 cuboctahedra, edges with six equivalent PaMg12 cuboctahedra, edges with twelve equivalent MgMg8Pa4 cuboctahedra, faces with four equivalent PaMg12 cuboctahedra, and faces with sixteen MgMg8Pa4 cuboctahedra. There are two shorter (3.23 Å) and two longer (3.31 Å) Mg–Pa bond lengths. Pa is bonded to twelve Mg atoms to form PaMg12 cuboctahedra that share corners with six equivalent PaMg12 cuboctahedra, corners with twelve MgMg8Pa4 cuboctahedra, edges with eighteen MgMg8Pa4 cuboctahedra, faces with eight equivalent PaMg12 cuboctahedra, and faces with twelve MgMg8Pa4 cuboctahedra.

36 MATERIALS SCIENCE↗