NMR evidence for the participation of a low-barrier hydrogen bond in the mechanism of delta 5-3-ketosteroid isomerase.

abstract：:Neural crest cell derivatives have been suggested to be involved in thymus development. We established nonlymphoid thymic stromal cell cultures capable of supporting T-cell differentiation. In these nonlymphoid cell cultures, we identified cells with phenotypic and biochemical markers specific for neuronal cells. Neur...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Screpanti I,Meco D,Scarpa S,Morrone S,Frati L,Gulino A,Modesti A

更新日期：1992-04-15 00:00:00

abstract：:A low molecular weight inhibitor of cell-free protein synthesis effective at subnanomolar concentrations is formed on incubation of cytoplasmic extracts from interferon-treated cells with double-stranded RNA and ATP. It can be conveniently synthesized by incubating a poly(I).poly(C)-Sepharose-bound enzyme fraction fro...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Kerr IM,Brown RE

更新日期：1978-01-01 00:00:00

abstract：:Drugs with poor oral bioavailability usually are administered by hypodermic injection, which causes pain, poor patient compliance, the need for trained personnel, and risk of infectious disease transmission. Transdermal (TD) delivery provides an excellent alternative, but the barrier of skin's outer stratum corneum (S...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Wermeling DP,Banks SL,Hudson DA,Gill HS,Gupta J,Prausnitz MR,Stinchcomb AL

更新日期：2008-02-12 00:00:00

abstract：:Symbiotic microbes impact the severity of a variety of diseases through regulation of T-cell development. However, little is known regarding the molecular mechanisms by which this is accomplished. Here we report that a secreted factor, Erdr1, is regulated by the microbiota to control T-cell apoptosis. Erdr1 expression...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Soto R,Petersen C,Novis CL,Kubinak JL,Bell R,Stephens WZ,Lane TE,Fujinami RS,Bosque A,O'Connell RM,Round JL

更新日期：2017-05-23 00:00:00

abstract：:Understanding how electric fields and their fluctuations in the active site of enzymes affect efficient catalysis represents a critical objective of biochemical research. We have directly measured the dynamics of the electric field in the active site of a highly proficient enzyme, Δ(5)-3-ketosteroid isomerase (KSI), i...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Jha SK,Ji M,Gaffney KJ,Boxer SG

更新日期：2011-10-04 00:00:00

abstract：:We stabilize nematic droplets with handles against surface tension-driven instabilities, using a yield-stress material as outer fluid, and study the complex nematic textures and defect structures that result from the competition between topological constraints and the elasticity of the nematic liquid crystal. We uncov...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Pairam E,Vallamkondu J,Koning V,van Zuiden BC,Ellis PW,Bates MA,Vitelli V,Fernandez-Nieves A

更新日期：2013-06-04 00:00:00

abstract：:The primary structures of the tomato planta macho and tomato apical stunt viroids have been determined, and probable secondary structures are proposed. Both viroids can assume the rodlike conformation with extensive base-pairing characteristic of all known viroids. Sequence homologies between the two viroids (75%) and...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Kiefer MC,Owens RA,Diener TO

更新日期：1983-10-01 00:00:00

abstract：:Ventilator-induced diaphragmatic dysfunction (VIDD) refers to the diaphragm muscle weakness that occurs following prolonged controlled mechanical ventilation (MV). The presence of VIDD impedes recovery from respiratory failure. However, the pathophysiological mechanisms accounting for VIDD are still not fully understo...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Matecki S,Dridi H,Jung B,Saint N,Reiken SR,Scheuermann V,Mrozek S,Santulli G,Umanskaya A,Petrof BJ,Jaber S,Marks AR,Lacampagne A

更新日期：2016-08-09 00:00:00

abstract：:We posit that feasible reversal of the growth of atmospheric CH(4) and other trace gases would provide a vital contribution toward averting dangerous anthropogenic interference with global climate. Such trace gas reductions may allow stabilization of atmospheric CO(2) at an achievable level of anthropogenic CO(2) emis...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Hansen J,Sato M

更新日期：2004-11-16 00:00:00

abstract：:Saccharomyces cerevisiae strains expressing the activated RAS2Val19 gene or lacking both cAMP phosphodiesterase genes, PDE1 and PDE2, have impaired growth control and display an acute sensitivity to heat shock. We have isolated two classes of mammalian cDNAs from yeast expression libraries that suppress the heat shock...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Colicelli J,Nicolette C,Birchmeier C,Rodgers L,Riggs M,Wigler M

更新日期：1991-04-01 00:00:00

abstract：:After more than two decades of study, many fundamental questions remain unanswered about the dynamics of glass-forming materials confined to thin films. Experiments and simulations indicate that free interfaces enhance dynamics over length scales larger than molecular sizes, and this effect strengthens at lower temper...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Ivancic RJS,Riggleman RA

更新日期：2020-10-13 00:00:00

abstract：:Previous studies have identified lipid-poor high density lipoproteins with electrophoretic pre-beta mobility as the initial acceptors of cell-derived cholesterol in human plasma. These lipoproteins contain apolipoprotein A-I (apo A-I) as their sole apolipoprotein. In the present study, incubation of human plasma with ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Huang Y,von Eckardstein A,Wu S,Maeda N,Assmann G

更新日期：1994-03-01 00:00:00

abstract：:The monoclonal antibodies (mAb) DA6.147, DA6.164, and HIG.48 against human Ia antigens, but not the W6/32 mAb against human class I major histocompatibility complex antigens or the anti-monocyte OKM1 and 63D3 mAb, stimulated monocytes to secrete interleukin 1 (IL-1). IL-1 was measured by its property of promoting the ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Palacios R

更新日期：1985-10-01 00:00:00

abstract：:Triglyceridemic response to a standard oral fat meal was determined in 28 healthy subjects and related to the levels of several lipids, lipoproteins, and apolipoproteins in the post-absorptive plasma. A fatty test meal was administered orally, and postprandial plasma triglyceride levels were determined. In the fasting...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Patsch JR,Karlin JB,Scott LW,Smith LC,Gotto AM Jr

更新日期：1983-03-01 00:00:00

abstract：:We previously identified rat8 in the pathway involved in epithelial cell differentiation that occurs in the rat mammary gland at pregnancy when tubules and alveoli are formed. rat8, which encodes an IFN-inducible membrane protein, is the rat homologue of the mouse gene fragilis. By differential detergent extraction an...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Zucchi I,Prinetti A,Scotti M,Valsecchi V,Valaperta R,Mento E,Reinbold R,Vezzoni P,Sonnino S,Albertini A,Dulbecco R

更新日期：2004-02-17 00:00:00

abstract：:Many cells exhibit periodic transient increases in cytosolic calcium levels rather than a sustained rise when stimulated by a hormone or growth factor. We propose here a molecular model that accounts for periodic calcium spiking induced by a constant stimulus. Four elements give rise to repetitive calcium transients: ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Meyer T,Stryer L

更新日期：1988-07-01 00:00:00

abstract：:We previously isolated a mutant of Escherichia coli that is preferentially affected in the synthesis of rRNA and has a mutation in the gene (accD) encoding a subunit of acetyl-CoA carboxylase. Using this mutant and other mutants of the pathway for fatty acid and phospholipid biosynthesis as well as cerulenin, a specif...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Seyfzadeh M,Keener J,Nomura M

更新日期：1993-12-01 00:00:00

abstract：:Colorectal cancer is the second leading cause of cancer-related deaths in the United States. Understanding the distinct genetic and epigenetic changes contributing to the establishment and growth of metastatic lesions is crucial for the development of novel therapeutic strategies. In a search for key regulators of col...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Rychahou PG,Kang J,Gulhati P,Doan HQ,Chen LA,Xiao SY,Chung DH,Evers BM

更新日期：2008-12-23 00:00:00

abstract：:Motilin, [Met]enkephalin, [Leu]enkephalin, somatostatin, taurine, gamma-aminobutyric acid (GABA), and glycine were tested for their effects on Deiters neurons of the lateral vestibular nucleus in rabbits. Iontophoresis was carried out with multibarrelled micropipettes. All four peptides and three amino acids produced ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Chan-Palay V,Ito M,Tongroach P,Sakurai M,Palay S

更新日期：1982-05-01 00:00:00

abstract：:A model chemical network involving reactions and diffusion is studied. Spatially and temporally ordered solutions of the equations are found by bifurcation theory. These solutions are calculated analytically and their stability is studied. Properties of these dissipative structures are discussed, and a comparison with...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Nicolis G,Auchmuty JF

更新日期：1974-07-01 00:00:00

abstract：:A complex between soluble dextran and human hemoglobin has been synthesized by two different methods. In the alkylation method, hemoglobin was allowed to react with bromoacetyl groups incorporated into the dextran; the yield of the complex was about 80% in terms of the hemoglobin used. In the dialdehyde method, hemogl...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Tam SC,Blumenstein J,Wong JT

更新日期：1976-06-01 00:00:00

abstract：:Early conformational events during folding of acyl-CoA binding protein (ACBP), an 86-residue alpha-helical protein, were explored by using a continuous-flow mixing apparatus with a dead time of 70 micros to measure changes in intrinsic tryptophan fluorescence and tryptophan-dansyl fluorescence energy transfer. Althoug...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Teilum K,Maki K,Kragelund BB,Poulsen FM,Roder H

更新日期：2002-07-23 00:00:00

abstract：:Gene knockout is the most powerful tool for determining gene function or permanently modifying the phenotypic characteristics of a cell. Existing methods for gene disruption are limited by their efficiency, time to completion, and/or the potential for confounding off-target effects. Here, we demonstrate a rapid single...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Santiago Y,Chan E,Liu PQ,Orlando S,Zhang L,Urnov FD,Holmes MC,Guschin D,Waite A,Miller JC,Rebar EJ,Gregory PD,Klug A,Collingwood TN

更新日期：2008-04-15 00:00:00

abstract：:Regulatory T (Treg) cells expressing the transcription factor Foxp3 play an important role in maintaining immune homeostasis. Chronic inflammation is associated with reduced Foxp3 expression, function, and loss of phenotypic stability. Previous studies have established the importance of TNF receptor 2 (TNFR2) in the g...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Tseng WY,Huang YS,Clanchy F,McNamee K,Perocheau D,Ogbechi J,Luo SF,Feldmann M,McCann FE,Williams RO

更新日期：2019-10-22 00:00:00

abstract：:Splenic cells from one BALB/c mouse and one C57/BL mouse, immunized with purified rat liver glucocorticoid receptor (GR), were fused with the mouse myeloma cell line Sp 2/0-Ag 14. Screening for production of anti-GR-antibodies by the hybridomas was carried out with an enzyme-linked immunosorbent assay, using partially...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Okret S,Wikström AC,Wrange O,Andersson B,Gustafsson JA

更新日期：1984-03-01 00:00:00

abstract：:Stimulation of antitumor immune mechanisms is the primary goal of cancer immunotherapy, and accumulating evidence suggests that effective alteration of the host-tumor relationship involves immunomodulating cytokines and also the presence of costimulatory molecules. To examine the antitumor effect of direct in vivo gen...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Pützer BM,Hitt M,Muller WJ,Emtage P,Gauldie J,Graham FL

更新日期：1997-09-30 00:00:00

abstract：:A topological model of the DNA binding site for the cyclic AMP receptor protein (CRP) is presented. A consensus sequence drawn from the known CRP binding sites has several symmetrical subregions that are spatially resolved onto different faces of the DNA helix. Consideration of available biochemical and genetic data s...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： O'Neill MC,Amass K,de Crombrugghe B

更新日期：1981-04-01 00:00:00

abstract：:Ubiquitination, the crucial posttranslational modification that regulates the eukaryotic proteome, is carried out by a trio of enzymes, known as E1 [ubiquitin (Ub)-activating enzyme], E2 (Ub-conjugating enzyme), and E3 (Ub ligase). Although most E2s can work with any of the three mechanistically distinct classes of E3...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Dove KK,Kemp HA,Di Bona KR,Reiter KH,Milburn LJ,Camacho D,Fay DS,Miller DL,Klevit RE

更新日期：2017-08-08 00:00:00

abstract：:Membranes were purified from rat muscle by a differential centrifugation method that avoids the use of salt extraction or incubations at elevated temperature. Three populations of membrane-limited vesicles were defined having average densities of 1.112 (fraction I), 1.141 (fraction II), and 1.158 (fraction III) g/ml i...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Barchi RL,Bonilla E,Wong M

更新日期：1977-01-01 00:00:00

abstract：:Murine mammary tumor virus (MMTV) expression is analyzed in a T-lymphoid cell line (T1M1) sensitive to the killing effect of glucocorticoids and in two of its variants, one resistant (T1M1r) and one supersensitive (T1M1ss) to glucocorticoid-induced lymphocytolysis. In the T1M1 line, MMTV is expressed and induced appro...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Mermod JJ,Bourgeois S,Defer N,Crépin M

更新日期：1983-01-01 00:00:00