Abstract:
:A synthetic polymer has been prepared which contains dodecyl groups (to bind small substrate molecules) and methyleneimidazole side chains (as nucleophilic catalytic sites) linked to a polyethyleneimine framework. This macromolecule, with a high local concentration of binding and catalytic groups, catalyzes the hydrolysis of uncharged nitrophenyl esters in water at pH 7 with rates markedly greater than previously observed with any other synthetic substances under similar conditions.
journal_name
Proc Natl Acad Sci U S Aauthors
Klotz IM,Royer GP,Scarpa ISdoi
10.1073/pnas.68.2.263subject
Has Abstractpub_date
1971-02-01 00:00:00pages
263-4issue
2eissn
0027-8424issn
1091-6490journal_volume
68pub_type
杂志文章abstract::The signal-transducing guanine nucleotide-binding regulatory (G) proteins are heterotrimers composed of three subunits--alpha, beta, and gamma. Although multiple distinctive forms of the alpha subunit have been described, only two forms of the beta subunits of the G proteins have been identified. To investigate furthe...
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.87.6.2329
更新日期:1990-03-01 00:00:00
abstract::Alkylation of DNA by 7r,8t-dihydroxy,9t,10t-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti-BPDE) forms mainly trans adducts (with respect to the C-9/10 positions). We recently described a halide-catalyzed pathway that preferentially generates cis adducts and now report that the trans chlorohydrin of anti-BPDE (trans-BP...
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.94.5.1749
更新日期:1997-03-04 00:00:00
abstract::A strain of Escherichia coli, selected on the basis of its resistance to colicin N, reveals distinct structural and functional alterations in unspecific OmpF porin. A single mutation [Gly-119-->Asp (G119D)] was identified in the internal loop L3 that contributes critically to the formation of the construction inside 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.91.22.10675
更新日期:1994-10-25 00:00:00
abstract::The mechanisms underlying analgesia related to social touch are not clear. While recent research highlights the role of the empathy of the observer to pain relief in the target, the contribution of social interaction to analgesia is unknown. The current study examines brain-to-brain coupling during pain with interpers...
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.1703643115
更新日期:2018-03-13 00:00:00
abstract::We report the heavy chain variable region sequences from the cDNAs of five previously described monoclonal cell lines producing human antibodies specific for the human immunodeficiency virus type 1 and detail the molecular characteristics, germ-line origins, and extent of somatic mutation among these antibodies. Three...
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.88.17.7783
更新日期:1991-09-01 00:00:00
abstract::Somatic copy number variations (CNVs) exist in the brain, but their genesis, prevalence, forms, and biological impact remain unclear, even within experimentally tractable animal models. We combined a transposase-based amplification (TbA) methodology for single-cell whole-genome sequencing with a bioinformatic approach...
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.1812702115
更新日期:2018-10-16 00:00:00
abstract::Most class I MHC ligands are generated from the vast majority of cellular proteins by proteolysis within the ubiquitin-proteasome pathway and are presented on the cell surface by MHC class I molecules. Here, we present the crystallographic analysis of yeast 20S proteasome in complex with the inhibitor homobelactosin C...
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.0600647103
更新日期:2006-03-21 00:00:00
abstract::RS67333 is a partial serotonin subtype 4 receptor (5-HT4R) agonist that has been widely studied for its procognitive effect. More recently, it has been shown that its ability to promote the nonamyloidogenic cleavage of the precursor of the neurotoxic amyloid-β peptide leads to the secretion of the neurotrophic protein...
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.1410315111
更新日期:2014-09-09 00:00:00
abstract::Animal mitochondrial DNA (mtDNA) maintains a displacement loop (D loop) at the heavy strand origin of replication. These D loops represent sharply limited synthesis of heavy strands and provide a unique opportunity to examine the termination of DNA synthesis. Direct sizing at the nucleotide level indicates that the 3'...
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.78.10.6116
更新日期:1981-10-01 00:00:00
abstract::We have developed a defective herpes simplex virus (HSV) vector system that permits the introduction of virtually any gene into mammalian central nervous system neurons. The prototype vector, pHSVlac, contains a transcription unit that places the Escherichia coli lacZ gene under the control of the HSV-1 immediate earl...
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.87.3.1149
更新日期:1990-02-01 00:00:00
abstract::Plant-made vaccines have been the subject of intense interest because they can be produced economically in large scale without the use of animal-derived components. Plant-made therapeutic vaccines against challenging chronic diseases, such as cancer, have received little research attention, and no previous human clini...
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.0803636105
更新日期:2008-07-22 00:00:00
abstract::Human fibroblast cells treated with a combination of inhibitors of protein and RNA synthesis [cycloheximide and actinomycin D as used to superinduce interferon beta (IFN-beta)] secrete two proteins with molecular masses of 22000 and 27000 kilodaltons (called 22-kDal and 27-kDal) that are precipitable with an antiserum...
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.79.9.2768
更新日期:1982-05-01 00:00:00
abstract::Unconscious neural activity has been repeatedly shown to precede and potentially even influence subsequent free decisions. However, to date, such findings have been mostly restricted to simple motor choices, and despite considerable debate, there is no evidence that the outcome of more complex free decisions can be pr...
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.1212218110
更新日期:2013-04-09 00:00:00
abstract::Thymidine kinase-deficient mouse L cells have been transformed with plasmid DNAs carrying 8-base-pair Xho I linker insertion mutations in the coding region of the herpes simplex virus type 1 thymidine kinase gene. When the mutant plasmids are introduced individually into LTK- cells, transformation efficiencies are gre...
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.80.15.4827
更新日期:1983-08-01 00:00:00
abstract::Viruses have unique lifestyles. To describe the pathogenesis and significance of viral infection in terms of host responses, resultant injury, and therapy, we focused on two RNA viruses: lymphocytic choriomeningitis (LCMV) and influenza (Flu). Many of the currently established concepts and consequences about viruses a...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章,评审
doi:10.1073/pnas.1222025110
更新日期:2013-03-12 00:00:00
abstract::Extracellular growth and differentiation factors induce changes in gene expression in the nucleus by initiating a series of protein associations that alter the subcellular localization of intracellular signaling proteins. Initial events involve receptor homo- or heterodimerization and subsequent recruitment of cytosol...
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.93.10.4604
更新日期:1996-05-14 00:00:00
abstract::Heavy (H) chain binding protein (BiP), which binds to free immunoglobulin H chain of the mu and gamma classes, can be demonstrated in pre-B-cells. It is proposed that the displacement of BiP from H chain by light (L) chain terminates the activity of the enzyme system, L-generase, which catalyzes DNA rearrangement at 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.79.22.6976
更新日期:1982-11-01 00:00:00
abstract::The human intestine is densely populated by a microbial consortium whose metabolic activities are influenced by, among others, bifidobacteria. However, the genetic basis of adaptation of bifidobacteria to the human gut is poorly understood. Analysis of the 2,214,650-bp genome of Bifidobacterium bifidum PRL2010, a stra...
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.1011100107
更新日期:2010-11-09 00:00:00
abstract::During the developmental process of the Gram-negative soil bacterium Myxococcus xanthus, vegetatively growing rod cells differentiate to ultimately become metabolically quiescent and environmentally resistant myxospores encased within fruiting bodies. This program, initiated by nutrient deprivation, is propagated by b...
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.0506969102
更新日期:2005-10-04 00:00:00
abstract::The effect of transformation by Rous sarcoma virus on the neural cell adhesion molecule N-CAM was assessed by immunoblotting, immunofluorescence staining, and an in vitro cell-cell aggregation assay using highly specific antibodies to the adhesion molecule. Expression of N-CAM was found to be temperature dependent in ...
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.81.3.969
更新日期:1984-02-01 00:00:00
abstract::The Kitaev model with an applied magnetic field in the [Formula: see text] direction shows two transitions: from a nonabelian gapped quantum spin liquid (QSL) to a gapless QSL at [Formula: see text] and a second transition at a higher field [Formula: see text] to a gapped partially polarized phase, where K is the stre...
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.1821406116
更新日期:2019-06-18 00:00:00
abstract::The phenomenon of selective translation of T4 template RNA by ribosomes from T4-infected cells, or factors derived therefrom, has been extended to studies on the initiation of protein synthesis. A high-salt extract derived from T4-infected ribosomes inhibits the formation of initiation complexes of MS2 and Escherichia...
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.67.2.696
更新日期:1970-10-01 00:00:00
abstract::Junctions that mediate excitation-contraction (e-c) coupling are formed between the sarcoplasmic reticulum (SR) and either the surface membrane or the transverse (T) tubules in normal skeletal muscle. Two structural components of the junctions, the feet of the SR and the tetrads of T tubules, have been identified resp...
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.92.8.3381
更新日期:1995-04-11 00:00:00
abstract::The potential benefits of autonomous systems are obvious. However, there are still major issues to be dealt with before developing such systems becomes a commonplace engineering practice, with accepted and trustworthy deliverables. We argue that a solid, evolving, publicly available, community-controlled foundation fo...
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.2003162117
更新日期:2020-07-28 00:00:00
abstract::We report a machine-learning strategy for design of organic structure directing agents (OSDAs) for zeolite beta. We use machine learning to replace a computationally expensive molecular dynamics evaluation of the stabilization energy of the OSDA inside zeolite beta with a neural network prediction. We train the neural...
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.1818763116
更新日期:2019-02-26 00:00:00
abstract::Multiple biological processes involve the stretching of nucleic acids (NAs). Stretching forces induce local changes in the molecule structure, inhibiting or promoting the binding of proteins, which ultimately affects their functionality. Understanding how a force induces changes in the structure of NAs at the atomic l...
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.1705642114
更新日期:2017-07-03 00:00:00
abstract::One of the factors required for the antiviral activity of the synthetic nucleoside, ribavirin (1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide), is the ability of the molecule to adopt the substrate conformation specified by the enzyme for which it is a competitive inhibitor, inosine 5'-phosphate dehydrogenase (IM...
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.73.12.4257
更新日期:1976-12-01 00:00:00
abstract::Epstein-Barr virus (EBV) latent infection membrane protein 1 (LMP1)-induced NF-kappaB activation is important for infected cell survival. LMP1 activates NF-kappaB, in part, by engaging tumor necrosis factor (TNF) receptor-associated factors (TRAFs), which also mediate NF-kappaB activation from LTbetaR and CD40. LTbeta...
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.2237183100
更新日期:2004-01-06 00:00:00
abstract::Myelinated fibers can be demonstrated in thin unstained brain sections of freshly killed uninjected animals. With this method myelinated fibers stand out as clearly as in stained Weigert sections from formalin-fixed brains. Unstained unfixed sections can be viewed under ordinary light within minutes after death of the...
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.71.3.598
更新日期:1974-03-01 00:00:00
abstract::Natural products have long served as both a source and inspiration for pharmaceuticals. Modifying the structure of a natural product often improves the biological activity of the compound. Metabolic engineering strategies to ferment "unnatural" products have been enormously successful in microbial organisms. However, ...
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.0903393106
更新日期:2009-08-18 00:00:00