Enantiomer excesses of rare and common sugar derivatives in carbonaceous meteorites.

abstract：:The neural cell adhesion molecule N-CAM is a sialic acid-rich, cell surface glycoprotein that mediates cell adhesion by a homophilic mechanism. Its binding function has been implicated in both morphogenesis and histogenesis; during development it changes in amount at the cell surface and perinatally it undergoes a dec...

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

authors： Hoffman S,Chuong CM,Edelman GM

更新日期：1984-11-01 00:00:00

abstract：:Fast axoplasmic transport was studied in dorsal root ganglion cells of the cat. Proteins carried in the fast axoplasmic flow were labeled after an intraganglionic injection of (L)-[4,5-(3)H]leucine. The rate of transport was 380 +/- 26 mm/day in both the central and peripheral branches of the bifurcating axons that ar...

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

authors： Anderson LE,McClure WO

更新日期：1973-05-01 00:00:00

abstract：:The virulent properties of the common human and livestock pathogen Clostridium perfringens are attributable to a formidable battery of toxins. Among these are a number of large and highly modular carbohydrate-active enzymes, including the mu-toxin and sialidases, whose catalytic properties are consistent with degradat...

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

authors： Adams JJ,Gregg K,Bayer EA,Boraston AB,Smith SP

更新日期：2008-08-26 00:00:00

abstract：:Understanding how institutional changes within academia may affect the overall potential of science requires a better quantitative representation of how careers evolve over time. Because knowledge spillovers, cumulative advantage, competition, and collaboration are distinctive features of the academic profession, both...

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

authors： Petersen AM,Riccaboni M,Stanley HE,Pammolli F

更新日期：2012-04-03 00:00:00

abstract：:The receptor for granulocyte-macrophage colony-stimulating factor (GM-CSF) is composed of an alpha and beta subunit, which together form the high-affinity receptor. The alpha subunit by itself binds ligand at low affinity, whereas the isolated beta subunit does not bind GM-CSF. It is generally believed that the high-a...

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

authors： Ding DX,Rivas CI,Heaney ML,Raines MA,Vera JC,Golde DW

更新日期：1994-03-29 00:00:00

abstract：:Pronounced bright and dark bands are seen at the bright and dark edges of half-shadows and similar distributions of illumination. These are the so-called Mach bands. A pair of vertical Mach bands was generated with a ramp pattern in the central strip of a horizontal tripartite oscilloscope display. This pattern consis...

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

authors： Ratliff F,Milkman N,Rennert N

更新日期：1983-07-01 00:00:00

abstract：:We have developed an efficient, versatile, and user-friendly viral engineering and expression system that is based on in planta assembly of functional viral vectors from separate pro-vector modules. With this new system, instead of supplying a plant cell with a complete viral vector as a mature viral particle, an RNA ...

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

authors： Marillonnet S,Giritch A,Gils M,Kandzia R,Klimyuk V,Gleba Y

更新日期：2004-05-04 00:00:00

abstract：:The rat W3/25 antigen was the first marker antigen of helper T lymphocytes to be identified. Subsequently, the human OKT4 antigen (now called CD4) was described, and cell distribution and functional data suggested that W3/25 and OKT4 antigens were homologous. This is now confirmed by the matching of peptide sequences ...

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

authors： Clark SJ,Jefferies WA,Barclay AN,Gagnon J,Williams AF

更新日期：1987-03-01 00:00:00

abstract：:Ferroelectricity has long been speculated to have important biological functions, although its very existence in biology has never been firmly established. Here, we present compelling evidence that elastin, the key ECM protein found in connective tissues, is ferroelectric, and we elucidate the molecular mechanism of i...

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

authors： Liu Y,Cai HL,Zelisko M,Wang Y,Sun J,Yan F,Ma F,Wang P,Chen QN,Zheng H,Meng X,Sharma P,Zhang Y,Li J

更新日期：2014-07-08 00:00:00

abstract：:We study atomic models of the thermodynamics of the structural transition of peptides that form alpha-helices. The effect of sequence variation on alpha-helix formation for alanine-rich peptides, Ac-Ala21-methyl amide (A21) and Ac-A5 (AAARA)3A-methyl amide (Fs peptide), is investigated by atomic simulation studies of ...

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

authors： García AE,Sanbonmatsu KY

更新日期：2002-03-05 00:00:00

abstract：:The GTP/GDP nucleotide switch in Ras superfamily GTPases generally involves differential affinity toward downstream effectors, with the GTP-bound state having a higher affinity for effector than the GDP-bound state. We have developed a quantitative model of allosteric regulation of the Wiskott-Aldrich syndrome protein...

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

authors： Leung DW,Rosen MK

更新日期：2005-04-19 00:00:00

abstract：:Salmonella enterica serovar Typhi can colonize the gallbladder and persist in an asymptomatic carrier state that is frequently associated with the presence of gallstones. We have shown that salmonellae form bile-mediated biofilms on human gallstones and cholesterol-coated surfaces in vitro. Here, we test the hypothesi...

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

authors： Crawford RW,Rosales-Reyes R,Ramírez-Aguilar Mde L,Chapa-Azuela O,Alpuche-Aranda C,Gunn JS

更新日期：2010-03-02 00:00:00

abstract：:Analysis of the activity and structure of lower vertebrate alcohol dehydrogenases reveals that relationships between the classical liver and yeast enzymes need not be continuous. Both the ethanol activity of class I-type alcohol dehydrogenase (alcohol:NAD+ oxidoreductase, EC 1.1.1.1) and the glutathione-dependent form...

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

authors： Danielsson O,Jörnvall H

更新日期：1992-10-01 00:00:00

abstract：:The binding of 125I-labeled wheat germ agglutinin (WGA) to parental and three distinct WGA-resistant Chinese hamster ovary cell lines possessing modified cell surface carbohydrate structures has been examined over a 10(6)-fold range of WGA concentrations. The Scatchard plot for WGA binding to parental cells was comple...

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

authors： Stanley P,Carver JP

更新日期：1977-11-01 00:00:00

abstract：:Biodistribution studies of a water-soluble radioactive metallofullerene compound have been conducted using BALB/c mice. To this end, a sample containing Hox@C82 (x = 1, 2) was purified and derivatized to prepare the water-soluble metallofullerol, Hox@C82(OH)y. This metallofullerol was then neutron-activated (165Ho[n,g...

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

authors： Cagle DW,Kennel SJ,Mirzadeh S,Alford JM,Wilson LJ

更新日期：1999-04-27 00:00:00

abstract：:RNA interference is an evolutionarily conserved process in which recognition of double-stranded RNA ultimately leads to posttranscriptional suppression of gene expression. This suppression is mediated by short (21- to 22-nt) small interfering RNAs (siRNAs), which induce degradation of mRNA based on complementary base ...

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

authors： Barton GM,Medzhitov R

更新日期：2002-11-12 00:00:00

abstract：:Mild oxidation of human serum low-density lipoprotein (LDL) converts the apoprotein from a nearly homogeneous component of high apparent molecular weight to a mixture of apparently lower molecular weight polypeptide components, as characterized by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. This protein...

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

authors： Schuh J,Fairclough GF Jr,Haschemeyer RH

更新日期：1978-07-01 00:00:00

abstract：:The stator ring of the bacterial flagellar motor is composed of the MotA and MotB proteins that act together to generate a turning force (torque) acting on the FliG ring of the rotor. The C-terminal domain of MotB (MotB-C) is believed to anchor the MotA/MotB complex to peptidoglycan (PG) of the cell wall. The first cr...

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

authors： Roujeinikova A

更新日期：2008-07-29 00:00:00

abstract：:Dehydroepiandrosterone (DHEA) is a neurosteroid with potential effects on neurogenesis and neuronal survival in humans. However, most studies on DHEA have been performed in rodents, and there is little direct evidence for biological effects on the human nervous system. Furthermore, the mechanism of its action is unkno...

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

authors： Suzuki M,Wright LS,Marwah P,Lardy HA,Svendsen CN

更新日期：2004-03-02 00:00:00

abstract：:The primary product of biological nitrogen fixation, ammonia, reversibly regulates nitrogenase activity in a variety of diazotrophs by a process called "NH4(+)-switch-off/on." Strong correlative evidence from work in Azospirillum lipoferum and Rhodospirillum rubrum indicates that this regulation involves both the inac...

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

authors： Fu H,Burris RH,Roberts GP

更新日期：1990-03-01 00:00:00

abstract：:Parathyroid hormone (PTH), the major calcium-regulating hormone, and norepinephrine (NE), the principal neurotransmitter of sympathetic nerves, regulate bone remodeling by activating distinct cell-surface G protein-coupled receptors in osteoblasts: the parathyroid hormone type 1 receptor (PTHR) and the β(2)-adrenergic...

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

authors： Hanyu R,Wehbi VL,Hayata T,Moriya S,Feinstein TN,Ezura Y,Nagao M,Saita Y,Hemmi H,Notomi T,Nakamoto T,Schipani E,Takeda S,Kaneko K,Kurosawa H,Karsenty G,Kronenberg HM,Vilardaga JP,Noda M

更新日期：2012-05-08 00:00:00

abstract：:Melittin messenger RNA from queen bee venom glands has been translated in a cell-free system from wheat germ. A product larger than promelittin is formed which has the carboxy-terminal sequence-Gln-Gln-GlyCOOH. Melittin and promelittin from venom glands terminate in -Gln-GlnCONH2. The possible role of the extra glycin...

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

authors： Suchanek G,Kreil G

更新日期：1977-03-01 00:00:00

abstract：:Lissencephaly is a severe brain malformation in humans. To study the function of the gene mutated in lissencephaly (LIS1), we deleted the first coding exon from the mouse Lis1 gene. The deletion resulted in a shorter protein (sLIS1) that initiates from the second methionine, a unique situation because most LIS1 mutati...

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

authors： Cahana A,Escamez T,Nowakowski RS,Hayes NL,Giacobini M,von Holst A,Shmueli O,Sapir T,McConnell SK,Wurst W,Martinez S,Reiner O

更新日期：2001-05-22 00:00:00

abstract：:Neural activity and neurotrophins induce synaptic remodeling in part by altering gene expression. A cDNA encoding a glycosylphoshatidylinositol-anchored protein was identified by screening for hippocampal genes that are induced by neural activity. This molecule, named neuritin, is expressed in postmitotic-differentiat...

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

authors： Naeve GS,Ramakrishnan M,Kramer R,Hevroni D,Citri Y,Theill LE

更新日期：1997-03-18 00:00:00

abstract：:The λ exonuclease is an ATP-independent enzyme that binds to dsDNA ends and processively digests the 5'-ended strand to form 5' mononucleotides and a long 3' overhang. The crystal structure of λ exonuclease revealed a toroidal homotrimer with a central funnel-shaped channel for tracking along the DNA, and a mechanism ...

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

authors： Zhang J,McCabe KA,Bell CE

更新日期：2011-07-19 00:00:00

abstract：:On a planet experiencing global environmental change, the governance of natural resources depends on sustained collective action by diverse populations. Engaging in such collective action can only build upon the foundation of human cognition in social-ecological settings. To help understand this foundation, we assess ...

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

authors： Freeman J,Baggio JA,Coyle TR

更新日期：2020-04-07 00:00:00

abstract：:The proteasome is responsible for degradation of substrates of the ubiquitin pathway. 20S proteasomes are cylindrical particles with subunits arranged in a stack of four heptameric rings. The outer rings are composed of alpha subunits, and the inner rings are composed of beta subunits. A well-characterized archaeal pr...

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

authors： Arendt CS,Hochstrasser M

更新日期：1997-07-08 00:00:00

abstract：:Embryonic stem cells can be induced in vitro, by coculture with the stromal line RP.0.10 and a mixture of interleukins 3, 6, and 7, to differentiate into T (Joro75+) and B (B-220+) lymphocyte progenitors and other (Thy-1+, PgP-1+, c-kit+, Joro75-, B-220-, F4/80-, Mac-1-) hemopoietic precursors. The progeny of in vitro...

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

authors： Gutierrez-Ramos JC,Palacios R

更新日期：1992-10-01 00:00:00

abstract：:The planarity of peptide bonds is an assumption that underlies decades of theoretical modeling of proteins. Peptide bonds strongly deviating from planarity are considered very rare features of protein structure that occur for functional reasons. Here, empirical analyses of atomic-resolution protein structures reveal t...

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

authors： Berkholz DS,Driggers CM,Shapovalov MV,Dunbrack RL Jr,Karplus PA

更新日期：2012-01-10 00:00:00

abstract：:In human financial and social systems, exchanges of information among individuals cause speculative bubbles, behavioral cascades, and other correlated actions that profoundly influence system-level function. Exchanges of information are also widespread in ecological systems, but their effects on ecosystem-level proces...

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

authors： Gil MA,Hein AM

更新日期：2017-05-02 00:00:00