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PubMed1992

Structure of tris(dicyclohexylphenylphosphine)gold(I) perchlorate.

[Au(P(C6H11)2(C6H5))3][ClO4], M(r) = 1119.59, trigonal, R3c, a = 13.192(5), c = 52.83 (2) A, V = 7962 (9) A3, Z = 6, Dx = 1.401 g cm-3, lambda(Mo K alpha) = 0.71073 A, mu = 29.5 cm-1, F(000) = 3468, T = 296 K, final R = 0.047 for 1321 unique observed reflections. The Au atom in the anion and the perchlorate ion in [Au(Cy2PhP)3][ClO4] lie on a threefold axis. The complex has an almost ideal trigonal-planar geometry, with an Au--P distance of 2.421 (3) A, P--Au--P angles of 119.9 (3) degrees, and the Au atom only 0.08 (2) A out of the plane defined by the three P atoms.

Chemical Phenomena↗
PubMed1999

Chiral recognition between host and guest: a binaphthyl-18-crown-6 host with D-phenylglycinium methyl ester perchlorate guest. A difficult structure solved with CRUNCH.

The complex between (R)-4,5,7,8,10,11,13,14,16,17-decahydro-2,19- diphenyldinaphtho[2,1-q:1',2'-s][1,4,7,- 10,13,16]hexaoxa[2,5,8,11,14,17,19]cycloicosaheptene {Chemical Abstracts name: (R)-4,5,7,8,10,11,13,14,16,17-decahydro-2,19- diphenyldinaphtho[2,1-q:1',2'-s][1,4,7,-10,13,16]hexaoxacycloic osin} and D-2-phenylglycinium methyl ester perchlorate, C9H12NO2+.ClO4-.C42H40O6.-H2O, crystallizes in the orthorhombic space group P2(1)2(1)2(1) with two C9H12NO2+.C42H40O6 complexes, two ClO4- ions and two molecules of water in the asymmetric unit. Crystal data: M(r) = 924.44, a = 23.048 (7), b = 34.383 (6), c = 11.992 (6) A, V = 9503 (6) A3, Z = 8, Dx = 1.292 Mg m-3, F(000) = 3904, mu(Cu K alpha) = 1.261 mm-1, T = 175 K, R = 0.0896 for all 7784 reflections, 1208 parameters refined in three blocks with 29 restraints. Nearly twenty years elapsed between the first data collection and the solution of the structure with the direct-methods program CRUNCH. The structural details are of interest because enantiomers of this host show a high degree of discrimination between enantiomers of alpha-amino acids and their esters. The crystal structure demonstrates the influence of C-H...O and C-H...pi interactions on the unexpected orientation of the guest in the host cavity. The same orientation is found in both of the unique complexes, and the geometric details are in agreement with solution studies.

Computer Simulation↗
PubMed1999

Crystallization and preliminary X-ray diffraction studies of perchloric acid soluble protein (PSP) from rat liver.

Perchloric acid soluble protein purified from the cytosol fraction of rat liver has been crystallized in a form suitable for high-resolution X-ray diffraction studies. Octahedral crystals reaching 0.5 mm in cross-sectional diameter were produced by the hanging-drop method using polyethylene glycol (Mr = 8 kDa) as precipitant. These crystals diffract to 2.44 A on an in-house X-ray source and to 1.8 A using a bending-magnet beamline at ESRF Grenoble. The crystals belong to the cubic space group P213 with a = 89.90 A and two molecules per asymmetric unit, as indicated from a Vm value of 2.12 A3 Da-1 and self-rotation function computation. Screening for heavy-atom derivatives identified a platinum compound and xenon that bind to the protein.

Animals↗
PubMed2005

Nuclear transfer of perchloric acid-soluble protein by endoplasmic reticulum stressors.

Perchloric acid-soluble protein (PSP) is highly conserved during evolution from bacteria to mammals. Although PSP has been recognized as an inhibitor of translation and proliferation in vitro, its precise biological role has not yet been elucidated. Since we previously found similar distributions for PSP and the endoplasmic reticulum (ER) and Golgi complex, the intracellular distribution of PSP was analyzed in more detail. Immunofluorescence studies indicated that PSP co-localized with the ER and Golgi complex, since the distribution pattern of PSP was well matched to both of these organelles. An immunoelectron microscopic study revealed PSP was located not only in the cytosol but also on the surface of the outer ER membrane. Since PSP was present on the ER, we speculated that it may be associated with ER function. Therefore, we analyzed whether or not the ER stress response, which is one of the ER functions, affected PSP expression. The results showed that various ER stressors (thapsigargin, A23187, tunicamycin, brefeldin A, and cisplatin) provoked a dramatic change in the localization of PSP from outside of the nucleus to inside the nucleus within 3 h. Moreover, the ER stressors induced PSP expression. These results suggest that PSP is involved in the cellular response to ER stressors, and that the change in localization of PSP from the ER to the nucleus may be associated with ER stress responses.

Active Transport, Cell Nucleus↗
PubMed2006

Reduced expression of perchloric acid-soluble protein after partial hepatectomy in rats.

We examined the expression of perchloric acid-soluble protein (PSP) during liver regeneration after partial hepatectomy (PH) in rats. Liver regeneration was almost complete at 7-d after PH. Expression of PSP protein and mRNA decreased and then gradually increased during liver regeneration. An immunohistochemical study showed that PSP is distributed in cytosol and nuclei in normal liver, but localization in the nuclei was not be recognized in the regenerated liver.

Animals↗
PubMedDate not supplied

Recombinant perchloric acid-soluble protein suppresses the immunoglobulin production of human-human hybridoma HB4C5 cells.

Because perchloric acid-soluble protein (PSP) has been conserved evolutionally in various species from Escherichia coli to humans, it may reflect an involvement in basic cellular regulation. However, the precise function of PSP is currently unknown. In this study, we examined the direct effect of PSP on the production of immunoglobulin (Ig) using human B, HB4C5, NAT-30, and U266 cells because it has been reported that subcutaneous administration of PSP affects rodent immune systems. Suppression of Ig productivity and decrement of the cell viability was recognized only in HB4C5 cells by the addition of PSP into the medium. On the other hand, PSP had no effect on Ig productivity and cell viability in NAT-30 and U266 cells. In addition, PSP was clearly incorporated by HB4C5 but not by the other cells. These results suggest that the Ig production suppressed by PSP, which has been previously reported to inhibit protein synthesis, contributed to the incorporation of PSP into the HB4C5 cells.

Animals↗
PubMed2006

Diffusion coefficients of C60 and C60- in benzonitrile and dichloromethane solutions containing tetrabutylammonium perchlorate, measured by potential-step chronoamperometry.

The diffusion coefficients of C(60) in dichloromethane and benzonitrile solutions containing 0.1 M tetrabutylammonium perchlorate were determined by single potential-step chronoamperometry at small disk electrodes. The diffusion coefficients of C(60) were obtained by curve fitting of the chronoamperograms to a theoretical equation by Shoup and Szabo. The values were (1.4 +/- 0.3) x 10(-9) and (4.1 +/- 0.3) x 10(-10) m(2) s(-1), respectively (the errors are 95% confidence limits). The diffusion coefficients of C(60)(-) in these solutions were measured by double potential-step chronoamperometry. The ratios of the diffusion coefficients of C(60) to those of C(60)(-) were obtained from theoretical curves of the ratios of the current at the second potential step to the current at the first one. The values of the ratios were 1.2 +/- 0.2 and 1.0 +/- 0.3, respectively.

Diffusion↗
PubMed1992

Superoxide radical production during the autoxidation of 1-methyl-4-phenyl-2,3-dihydropyridinium perchlorate.

1-Methyl-4-phenyl-2,3-dihydropyridinium perchlorate (MPDP+), an intermediate in the metabolism of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, was found to generate superoxide radicals during its autoxidation process. The generation of superoxide radicals was detected by their ability to reduce ferricytochrome c. Superoxide dismutase inhibited this reduction in a dose-dependent manner. The rate of reduction of ferricytochrome c was dependent not only on the concentration of MPDP+ but also on the pH of the system. Thus, the rate of autoxidation of MPDP+ and the sensitivity of this autoxidation to superoxide dismutase-inhibitable ferricytochrome c reduction were both augmented, as the pH was raised from 7.0 to 10.5. The rate constant (Kc) for the reaction of superoxide radical with ferricytochrome c to form ferricytochrome c was found to be 3.48 x 10(5) M-1 s-1. The rate constant (KMPDP+) for the reaction of MPDP+ with ferricytochrome3+ c was found to be only 4.86 M-1 s-1. These results, in conjunction with complexities in the kinetics, lead to the proposal that autoxidation of MPDP+ proceeds by at least two distinct pathways, one of which involves the production of superoxide radicals and hence is inhibitable by superoxide dismutase. It is possible that the free radicals so generated could induce oxidative injury which may be central to the MPTP/MPDP(+)-induced neuropathy.

Cytochrome c Group↗
PubMed1985

Cell wall lytic enzyme released by mating gametes of Chlamydomonas reinhardtii is a metalloprotease and digests the sodium perchlorate-insoluble component of cell wall.

Chlamydomonas lytic enzyme of the cell wall, which is released during agglutination of gametes of opposite mating types, has been characterized as a metalloprotease. The purified enzyme contains zinc. Removal of zinc with EDTA results in an inactive, metal-free apoenzyme, and Co2+ restores the activity most effectively. Among various protease inhibitors of microbial origin, pepstatin A, chymostatin, antipain, leupeptin, and E-64 do not inactivate the enzyme, whereas phosphoramidon causes a complete loss of lytic activity. Cysteine, histidine, aspartic acid, and glutamic acid also inhibit the activity. The lytic enzyme splits casein and RNase A into several polypeptides of lower molecular masses. To determine which polypeptides of the cell wall are sensitive to the lytic enzyme, we first separated the intact cell walls into sodium perchlorate-soluble and -insoluble components, treated them with enzyme, and then analyzed them by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining. We conclude that only 2 of 16 polypeptides are digested by exposure to the enzyme and that the sensitive polypeptides belong to the salt-insoluble component of the cell wall. The mechanism of cell wall digestion with the lytic enzyme is discussed.

Cell Wall↗
PubMedDate not supplied

[Muscle glycoproteins (soluble in perchloric acid) after denervation and drug stimulation].

Muscle proteins soluble in perchloric acid contain about 75% of carbohydrates presented by neutral hexoses, fucose and hexuronic acids. Three days and two weeks after denervation the content of the glycoproteids protein part is unchanged, a month later it increases by 116%. The content of carbohydrate component following denervation lowers considerably and a month later is on the average 40% higher than in the muscle of healthy rats. Administration of muscular RNA restores the content of the protein component only by the end of a month; administration of pyrogenal normalizes the content of both protein and carbohydrate components.

Animals↗