Abstract:
:A cDNA containing the full coding region of human cytochrome b5 was inserted into a vaccinia virus cDNA expression vector. Infection of human thymidine kinase-minus (TK-) 143 cells in culture with this recombinant virus resulted in production of 0.3 nmol of cytochrome b5 per mg of cell lysate protein. The expressed cytochrome had a reduced difference spectrum with a Soret peak at 424 nm, typical of pure cytochrome b5. TK- 143 cells have little detectable endogenous cytochrome b5, cytochrome P-450 (P450), and NADPH-P450 oxidoreductase. To test whether cytochrome b5 potentiated mixed-function monooxygenation in situ, these cells were coinfected with three recombinant vaccinia viruses individually carrying cDNAs encoding cytochrome b5, NADPH-P450 oxidoreductase, and P450 form IIB1. These triple-virus-infected cells were compared to cells infected with the P450IIB1 and NADPH-P450 oxidoreductase recombinant viruses with respect to P450IIB1-catalyzed monooxygenase activities. Cytochrome b5 specifically augmented the deethylation of p-nitrophenetole in microsomal membrane fractions of infected cells or when substrate was incubated directly with cells in situ. No significant increases were seen with P450IIB1-catalyzed testosterone, 7-ethoxycoumarin, or 7-pentoxyresorufin oxidations. These data demonstrate that cytochrome b5 is capable of specifically augmenting monooxygenase activities in intact cells.
journal_name
Proc Natl Acad Sci U S Aauthors
Aoyama T,Nagata K,Yamazoe Y,Kato R,Matsunaga E,Gelboin HV,Gonzalez FJdoi
10.1073/pnas.87.14.5425subject
Has Abstractpub_date
1990-07-01 00:00:00pages
5425-9issue
14eissn
0027-8424issn
1091-6490journal_volume
87pub_type
杂志文章abstract::Stroke patients with small central nervous system infarcts often demonstrate an acute dysexecutive syndrome characterized by difficulty with attention, concentration, and processing speed, independent of lesion size or location. We use magnetoencephalography (MEG) to show that disruption of network dynamics may be res...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.2013231117
更新日期:2020-12-29 00:00:00
abstract::Ca2+-induced inhibition of alpha1C voltage-gated Ca2+ channels is a physiologically important regulatory mechanism that shortens the mean open time of these otherwise long-lasting high-voltage-activated channels. The mechanism of action of Ca2+ has been a matter of some controversy, as previous studies have proposed t...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.96.5.2435
更新日期:1999-03-02 00:00:00
abstract::Legionella pneumophila is the cause of Legionnaires' disease, which is a form of potentially fatal pneumonia. To identify genes required for virulence of the bacterium, a library of 1,386 L. pneumophila signature tagged transposon mutants was studied for guinea pig virulence. The mutants were screened in pools of 96 e...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.96.14.8190
更新日期:1999-07-06 00:00:00
abstract::Hexamethylene bisacetamide (HMBA) induces in vitro the cytodifferentiation of PCC3/A/1 mouse embryonal carcinoma (EC) cells. In EC cells, actin is associated with surface structures but microfilament bundles are not seen. After 2 days of HMBA treatment, rounded EC cells are converted to flat adhesive ones with a devel...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.76.4.1891
更新日期:1979-04-01 00:00:00
abstract::A recently discovered family of natural anion channelrhodopsins (ACRs) have the highest conductance among channelrhodopsins and exhibit exclusive anion selectivity, which make them efficient inhibitory tools for optogenetics. We report analysis of flash-induced absorption changes in purified wild-type and mutant ACRs,...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1525269113
更新日期:2016-04-05 00:00:00
abstract::Acetyl-CoA synthase from Clostridium thermoaceticum (ACS(Ct)) is an alpha(2)beta(2) tetramer containing two novel Ni-X-Fe(4)S(4) active sites (the A and C clusters) and a standard Fe(4)S(4) cluster (the B cluster). The acsA and acsB genes encoding the enzyme were cloned into Escherichia coli strain JM109 and overexpre...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.220404397
更新日期:2000-11-07 00:00:00
abstract::Five patients with advanced breast cancer were treated with pooled dialyzable transfer factor from healthy adult donors. The period of treatment ranged from 21 to 310 days, the total dose from 20 to 257 ml. Transfer factor did not elicit inflammatory or hypersensitivity reactions or detectable formation of antibody to...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.71.6.2319
更新日期:1974-06-01 00:00:00
abstract::Proofreading mechanisms increase specificity in biochemical reactions by allowing for the dissociation of intermediate complexes. These mechanisms disrupt and reset the reaction to undo errors at the cost of increased time of reaction and free energy expenditure. Here, we draw an analogy between proofreading and micro...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1119911109
更新日期:2012-07-24 00:00:00
abstract::Responses of tethered cells of Escherichia coli to impulse, step, exponential-ramp or exponentiated sine-wave stimuli are internally consistent, provided that allowance is made for the nonlinear effect of thresholds. This result confirms that wild-type cells exposed to stimuli in the physiological range make short-ter...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.83.23.8987
更新日期:1986-12-01 00:00:00
abstract::Chloroplast DNA (cpDNA) is under great photooxidative stress, yet its evolution is very conservative compared with nuclear or mitochondrial genomes. It can be expected that DNA repair mechanisms play important roles in cpDNA survival and evolution, but they are poorly understood. To gain insight into how the most seve...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1004326107
更新日期:2010-08-03 00:00:00
abstract::Inhomogeneous ab initio molecular dynamics simulations show that vaporization of MgSiO3 is incongruent and that the vapor phase is dominated by SiO and O2 molecules. The vapor is strongly depleted in Mg at low temperature and approaches the composition of the liquid near the critical point. We find that the liquid-vap...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1719134115
更新日期:2018-05-22 00:00:00
abstract::A tetramer of the Mu transposase (MuA) pairs the recombination sites, cleaves the donor DNA, and joins these ends to a target DNA by strand transfer. Juxtaposition of the recombination sites is accomplished by the assembly of a stable synaptic complex of MuA protein and Mu DNA. This initial critical step is facilitate...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.93.3.1146
更新日期:1996-02-06 00:00:00
abstract::A family of nanoscale-sized supramolecular cage compounds with a polyhedral framework is prepared by self-assembly from tritopic building blocks and rectangular corner units via noncovalent coordination interactions. These highly symmetrical cage compounds are described as face-directed, self-assembled truncated tetra...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.030264697
更新日期:2000-02-15 00:00:00
abstract::We have inserted a fourth protein ligand into the zinc coordination polyhedron of carbonic anhydrase II (CAII) that increases metal affinity 200-fold (Kd = 20 fM). The three-dimensional structures of threonine-199-->aspartate (T199D) and threonine-199-->glutamate (T199E) CAIIs, determined by x-ray crystallographic met...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.92.11.5017
更新日期:1995-05-23 00:00:00
abstract::Metabolomic markers associated with incident central adiposity gain were investigated in young adults. In a 9-mo prospective study of university freshmen (n = 264). Blood samples and anthropometry measurements were collected in the first 3 d on campus and at the end of the year. Plasma from individuals was pooled by p...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1620079114
更新日期:2017-05-23 00:00:00
abstract::Three enzyme reactions have been reported to catalyze the synthesis of phosphoribosylamine in eukaryotic cells. These activities are glutamine phosphoribosylpyrophosphate (P-Rib-P-P) amidotransferase [amidophosphoribosyl-transferase; 5-phosphoribosylamine: pyrophosphate phosphoribosyltransferase (glutamate-amidating) ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.73.7.2458
更新日期:1976-07-01 00:00:00
abstract::The Atg20 and Snx4/Atg24 proteins have been identified in a screen for mutants defective in a type of selective macroautophagy/autophagy. Both proteins are connected to the Atg1 kinase complex, which is involved in autophagy initiation, and bind phosphatidylinositol-3-phosphate. Atg20 and Snx4 contain putative BAR dom...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1708367114
更新日期:2017-11-21 00:00:00
abstract::The vacuolated lens (vl) mouse mutant causes congenital cataracts and neural tube defects (NTDs), with the NTDs being caused by abnormal neural fold apposition and fusion. Our positional cloning of vl indicates these phenotypes result from a deletion mutation in an uncharacterized orphan G protein-coupled receptor (GP...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0705657105
更新日期:2008-02-12 00:00:00
abstract::Methane can be converted to triose dihydroxyacetone (DHA) by chemical processes with formaldehyde as an intermediate. Carbon dioxide, a by-product of various industries including ethanol/butanol biorefineries, can also be converted to formaldehyde and then to DHA. DHA, upon entry into a cell and phosphorylation to DHA...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1801002115
更新日期:2018-04-24 00:00:00
abstract::The lactose permease (LacY) of Escherichia coli, a paradigm for the major facilitator superfamily, catalyzes the coupled stoichiometric translocation of a galactopyranoside and an H(+) across the cytoplasmic membrane. To catalyze transport, LacY undergoes large conformational changes that allow alternating access of s...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1404446111
更新日期:2014-04-22 00:00:00
abstract::Mobilization of the T-cell response against cancer has the potential to achieve long-lasting cures. However, it is not known how to harness antigen-presenting cells optimally to achieve an effective antitumor T-cell response. In this study, we show that anti-CD47 antibody-mediated phagocytosis of cancer by macrophages...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1305569110
更新日期:2013-07-02 00:00:00
abstract::UT-1 cells are a clone of Chinese hamster ovary cells that were selected to grow in the presence of compactin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A reductase [mevalonate: NADP+ oxidoreductase (CoA-acylating), EC 1.1.1.34]. These cells have 100- to 1,000-fold more immunoprecipitable reductas...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.79.17.5205
更新日期:1982-09-01 00:00:00
abstract::Tissue cultures of Actinidia kolomikta can be maintained as callus through repeated passages on a nutrient medium devoid of cytokinin but containing inorganic nutrients, sucrose, and other basal organics plus auxin. Under these conditions, actively growing callus contained 2 and 0.5 nmol of the cytokinins zeatin [io(6...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.83.4.972
更新日期:1986-02-01 00:00:00
abstract::Cosuppression results in the degradation of RNA from host genes and homologous transgenes after transcription in the nucleus. By using grafting experiments, we have shown previously that a systemic signal mediates the propagation of cosuppression of Nia host genes and 35S-Nia2 transgenes from silenced 35S-Nia2 transge...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.16.9675
更新日期:1998-08-04 00:00:00
abstract::The origin recognition complex (ORC) binds sites from which DNA replication is initiated. We address ORC binding selectivity in vivo by mapping ∼52,000 ORC2 binding sites throughout the human genome. The ORC binding profile is broader than those of sequence-specific transcription factors, suggesting that ORC is not bo...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1609060113
更新日期:2016-08-16 00:00:00
abstract::Chromosome 14 was transferred into tumorigenic nasopharyngeal carcinoma and esophageal carcinoma cell lines by a microcell-mediated chromosome transfer approach. Functional complementation of defects present in the cancer cells suppressed tumor formation. A candidate tumor-suppressor gene, cysteine-rich intestinal pro...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1101747108
更新日期:2011-05-17 00:00:00
abstract::The amino-terminal sequences of two polypeptides with nonsuppressible insulin-like and cell-growth-promoting activities (NSILA I and II), isolated from human serum, were determined. Of the first 31 residues, 22 are identical in NSILA I and II. Moreover, a striking structural similarity was found between NSILA and insu...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.73.12.4379
更新日期:1976-12-01 00:00:00
abstract::The charge density distribution of a protein has been refined experimentally. Diffraction data for a crambin crystal were measured to ultra-high resolution (0.54 A) at low temperature by using short-wavelength synchrotron radiation. The crystal structure was refined with a model for charged, nonspherical, multipolar a...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.97.7.3171
更新日期:2000-03-28 00:00:00
abstract::We have found that in the gill- and siphon- withdrawal reflex of Aplysia, the memory for short-term sensitization grades smoothly into long-term memory with increased amounts of sensitization training. One cellular locus for the storage of the memory underlying short-term sensitization is the set of monosynaptic conne...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.82.23.8266
更新日期:1985-12-01 00:00:00
abstract::Thiazides and related diuretics inhibit NaCl reabsorption in the distal tubule through an unknown mechanism. We report here that [3H]metolazone, a diuretic with a thiazide-like mechanism of action, labels a site in rat kidney membranes that has characteristics of the thiazide-sensitive ion transporter. [3H]Metolazone ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.7.2311
更新日期:1988-04-01 00:00:00