Abstract:
:The structural requirements of E. coli formylmethionine tRNA for aminoacylation have been examined by chemical modification of the tRNA, followed by separation of the modified molecules into active and inactive components. Photooxidation of tRNA(fMet) at 50 degrees in the presence of methylene blue results in modification of two guanosine (G) residues in the acceptor stem, at positions no. 2 and no. 71 from the 5'-phosphate terminus. Both of these modifications are present in inactive molecules, but only the G residue at position no. 2 is modified in the acceptor stem of active molecules. Loss of methionine acceptance occurs with first-order kinetics, indicating that inactivation by modification of G residue no. 71 is independent of any other modifications taking place under these conditions. The presence of a modified G residue at position no. 2 in the acceptor stem of active photooxidized molecules shows that disruption of normal base-pairing in this region is not sufficient to inactivate tRNA(fMet). These data indicate that the inactivating modification at position no. 71 is lethal due to a specific alteration in the nucleotide base, rather than simply as a result of breaking a hydrogen-bonded base pair in the acceptor stem.
journal_name
Proc Natl Acad Sci U S Aauthors
Schulman LHdoi
10.1073/pnas.69.12.3594subject
Has Abstractpub_date
1972-12-01 00:00:00pages
3594-7issue
12eissn
0027-8424issn
1091-6490journal_volume
69pub_type
杂志文章abstract::The effect of fluctuations in rate constants on the kinetic behavior of cyclic reacting systems, caused by a fluctuating external parameter, is studied. It is shown (i) that the stochastic properties of the system can be analyzed analytically by using the usual master equation approach when the external parameter is f...
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.84.3.729
更新日期:1987-02-01 00:00:00
abstract::Direct visualization of genomic loci in the 3D nucleus is important for understanding the spatial organization of the genome and its association with gene expression. Various DNA FISH methods have been developed in the past decades, all involving denaturing dsDNA and hybridizing fluorescent nucleic acid probes. Here w...
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.1515692112
更新日期:2015-09-22 00:00:00
abstract::An enzyme that reduces methionine sulfoxide [Met(O)] residues in proteins [peptide Met(O) reductase (MsrA), EC 1.8.4.6; originally identified in Escherichia coli] was purified from bovine liver, and the cDNA encoding this enzyme was cloned and sequenced. The mammalian homologue of E. coli msrA (also called pmsR) cDNA ...
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.93.5.2095
更新日期:1996-03-05 00:00:00
abstract::The 24 nucleotides comprising the carbohydrate-recognition domain of Maackia amurensis hemagglutinin (MAH) cDNA were randomly mutated. The mutant lectins were expressed as glutathione-S-transferase fusion proteins in Escherichia coli and 16 clones were randomly chosen. Although all of 16 recombinant lectins reacted st...
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.041621998
更新日期:2001-02-27 00:00:00
abstract::Many bacteria use acyl homoserine lactone signals to monitor cell density in a type of gene regulation termed quorum sensing and response. Synthesis of these signals is directed by homologs of the luxi gene of Vibrio fischeri. This communication resolves two critical issues concerning the synthesis of the V. fischeri ...
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.93.18.9505
更新日期:1996-09-03 00:00:00
abstract::The ability of the isolated perfused rat liver to differentiate between chylomicrons and remnants with either high or low apoprotein E:C ratios was investigated. Remnants were prepared in hepatectomized rats injected with chylomicrons double-labeled with [3H]cholesterol and 14C-labeled fatty acids. By densitometric sc...
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.81.18.5863
更新日期:1984-09-01 00:00:00
abstract::The fossil record of land plants is an obvious source of information on the dynamics of mass extinctions in the geological past. In conjunction with the end-Permian ecological crisis, approximately 250 million years ago, palynological data from East Greenland reveal some unanticipated patterns. We document the signifi...
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.131218098
更新日期:2001-07-03 00:00:00
abstract::IL-17 has been implicated in a number of inflammatory diseases, but the conditions of antigen exposure that drive the generation of Th17 responses have not been well defined. Epicutaneous (EC) immunization of mice with ovalbumin (OVA), which causes allergic skin inflammation with many characteristics of the skin lesio...
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.0706942104
更新日期:2007-10-02 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
pub_type: 杂志文章
doi:10.1073/pnas.242594499
更新日期:2002-11-12 00:00:00
abstract::We present molecular dating analyses for land plants that incorporate 33 fossil calibrations, permit rates of molecular evolution to be uncorrelated across the tree, and take into account uncertainties in phylogenetic relationships and the fossil record. We attached a prior probability to each fossil-based minimum age...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 历史文章,杂志文章
doi:10.1073/pnas.1001225107
更新日期:2010-03-30 00:00:00
abstract::In Xenopus oocytes injected with rat brain mRNA, as in neurons, glycine greatly potentiated responses of the N-methyl-D-aspartate (NMDA) type of excitatory amino acid receptor. Injected oocytes generated a partially desensitizing inward current in response to NMDA with 30 nM added glycine. As the added glycine concent...
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.87.6.2354
更新日期:1990-03-01 00:00:00
abstract::Factor XI (plasma thromboplastin antecedent) deficiency is a blood coagulation abnormality occurring in high frequency in Ashkenazi Jews. Three independent point mutations that result in a blood coagulation abnormality have been identified in the factor XI gene of six unrelated Ashkenazi patients. These mutations eith...
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.86.20.7667
更新日期:1989-10-01 00:00:00
abstract::Most paleo-episodes of ocean acidification (OA) were either too slow or too small to be instructive in predicting near-future impacts. The end-Cretaceous event (66 Mya) is intriguing in this regard, both because of its rapid onset and also because many pelagic calcifying species (including 100% of ammonites and more 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.1418604112
更新日期:2015-05-26 00:00:00
abstract::UV-sensitive syndrome (UVsS) is a rare autosomal recessive disorder characterized by photosensitivity and mild freckling but without neurological abnormalities or skin tumors. UVsS cells show UV hypersensitivity and defective transcription-coupled DNA repair of UV damage. It was suggested that UVsS does not belong 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.0404587101
更新日期:2004-10-26 00:00:00
abstract::Human T cell leukemia virus type 1 (HTLV-1) has evolved a remarkable strategy to thwart the antiviral effects of the cellular cytidine deaminase APOBEC3G (hA3G). HTLV-1 infects T lymphocytes in vivo, where, like HIV-1, it is likely to encounter hA3G. HIV-1 counteracts the innate antiviral activity of hA3G by producing...
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.0609444104
更新日期:2007-02-20 00:00:00
abstract::Homopyrimidine oligonucleotides bind to the major groove of a complementary homopyrimidine.homopurine stretch by triple helix formation. The bla gene from transposon Tn3 contains a homopyrimidine.homopurine sequence of 13 base pairs located just downstream of the RNA polymerase binding site. A 13-mer homopyrimidine ol...
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.89.2.504
更新日期:1992-01-15 00:00:00
abstract::Ubiquitination regulates, via different modes of modifications, a variety of biological processes, and aberrations in the process have been implicated in the pathogenesis of several neurodegenerative diseases. However, our ability to dissect the pathophysiological relevance of the ubiquitination code has been hampered...
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.1315654110
更新日期:2013-10-29 00:00:00
abstract::Chromophore-assisted light inactivation (CALI) offers the only method capable of modulating specific protein activities in localized regions and at particular times. Here, we generalize CALI so that it can be applied to a wider range of tasks. Specifically, we show that CALI can work with a genetically inserted epitop...
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.95.8.4293
更新日期:1998-04-14 00:00:00
abstract::14-3-3 proteins are ubiquitously expressed regulators of various cellular functions, including proliferation, metabolism, and differentiation, and altered 14-3-3 expression is associated with development and progression of cancer. We report a transforming 14-3-3 oncoprotein, which we identified through conventional cy...
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.1115528109
更新日期:2012-01-17 00:00:00
abstract::Significant efforts have been directed to understanding the factors that influence the lineage commitment of stem cells. This paper demonstrates that cell shape, independent of soluble factors, has a strong influence on the differentiation of human mesenchymal stem cells (MSCs) from bone marrow. When exposed to compet...
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.0903269107
更新日期:2010-03-16 00:00:00
abstract::Fluorescence of quinacrine in the presence of different polynucleotides was studied to attempt to identify the specific nucleotides responsible for the fluorescence of stained chromosome preparations. A marked enhancement of fluorescence was seen in the presence of bihelical polynucleotides, such as poly(dA-dT), poly(...
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.69.3.629
更新日期:1972-03-01 00:00:00
abstract::Calcium, a universal second messenger, regulates diverse cellular processes in eukaryotes. Ca2+ and Ca2+/calmodulin-regulated protein phosphorylation play a pivotal role in amplifying and diversifying the action of Ca(2+)-binding domain was cloned and characterized from lily. The cDNA clone contains an open reading fr...
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.92.11.4897
更新日期:1995-05-23 00:00:00
abstract::Imaging reporter gene expression in living subjects is a rapidly evolving area of molecular imaging research. Studies have validated the use of reporter genes with positron emission tomography (PET), single photon emission computed tomography (SPECT), MRI, fluorescence with wild-type and mutants of green fluorescent 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.012611099
更新日期:2002-01-08 00:00:00
abstract::Synaptic transmission of the light response from photoreceptors to second-order cells of the retina was studied with the whole-cell patch-clamp technique in tiger salamander (Ambystoma tigrinum) retinal slices. Synaptic strength is modulated by extracellular pH in a striking manner: Light-sensitive postsynaptic curren...
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.90.21.10081
更新日期:1993-11-01 00:00:00
abstract::cDNA clones for the (S)-tetrahydroberberine (H4Ber) oxidase of cultured berberine-producing Coptis japonica cells were isolated by screening a C. japonica cDNA library with synthetic nucleotides that can encode the NH2-terminal sequence of this enzyme. Analyses of the nucleotide sequences of the cloned cDNA inserts re...
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.86.2.534
更新日期:1989-01-01 00:00:00
abstract::Sequestration, the adherence of infected erythrocytes containing late developmental stages of the parasite (trophozoites and schizonts) to the endothelium of capillaries and venules, is characteristic of Plasmodium falciparum infections. We have studied two host factors, the spleen and antibody, that influence sequest...
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.80.16.5075
更新日期:1983-08-01 00:00:00
abstract::The release of catecholamines from adrenal chromaffin cells is known to be blocked by dihydropyridines, such as nitrendipine, and enhanced by others, such as BAY K8644. On the other hand, release from sympathetic neurons is predominantly insensitive to these agents. Release of [3H]norepinephrine from undifferentiated ...
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.83.7.2243
更新日期:1986-04-01 00:00:00
abstract::Previous studies in Saccharomyces cerevisiae have defined an essential role for the Dbf4-Cdc7 kinase complex in the initiation of DNA replication presumably by phosphorylation of target proteins, such as the minichromosome maintenance (Mcm) complex. We have examined the phosphorylation of the Mcm complex by the Dfp1-H...
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.0237384100
更新日期:2003-03-04 00:00:00
abstract::Engaging mammalian Toll-like receptors (TLRs) activate both the NF-kappaB and mitogen-activated protein kinase signaling pathways. Here we establish that mitogen-activated protein 3 kinase Tpl2, levels of which are markedly reduced in nfkb1(-/-) cells, is required for extracellular signal-regulated kinase (ERK) activa...
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.0511113103
更新日期:2006-02-28 00:00:00
abstract::Intrinsically disordered proteins (IDPs) are characterized by a lack of defined structure. Instead, they populate ensembles of rapidly interconverting conformations with marginal structural stabilities. Changes in solution conditions such as temperature and crowding agents consequently affect IDPs more than their fold...
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.1705105114
更新日期:2017-09-12 00:00:00