Abstract:
:A coenzyme B12-dependent ribonucleotide reductase was purified from the archaebacterium Thermoplasma acidophila and partially sequenced. Using probes derived from the sequence, the corresponding gene was cloned, completely sequenced, and expressed in Escherichia coli. The deduced amino acid sequence shows that the catalytic domain of the B12-dependent enzyme from T. acidophila, some 400 amino acids, is related by common ancestry to the diferric tyrosine radical iron(III)-dependent ribonucleotide reductase from E. coli, yeast, mammalian viruses, and man. The critical cysteine residues in the catalytic domain that participate in the thiyl radical-dependent reaction have been conserved even though the cofactor that generates the radical is not. Evolutionary bridges created by the T. acidophila sequence and that of a B12-dependent reductase from Mycobacterium tuberculosis establish homology between the Fe-dependent enzymes and the catalytic domain of the Lactobacillus leichmannii B12-dependent enzyme as well. These bridges are confirmed by a predicted secondary structure for the Lactobacillus enzyme. Sequence similarities show that the N-terminal domain of the T. acidophila ribonucleotide reductase is also homologous to the anaerobic ribonucleotide reductase from E. coli, which uses neither B12 nor Fe cofactors. A predicted secondary structure of the N-terminal domain suggests that it is predominantly helical, as is the domain in the aerobic E. coli enzyme depending on Fe, extending the homologous family of proteins to include anaerobic ribonucleotide reductases, B12 ribonucleotide reductases, and Fe-dependent aerobic ribonucleotide reductases. A model for the evolution of the ribonucleotide reductase family is presented; in this model, the thiyl radical-based reaction mechanism is conserved, but the cofactor is chosen to best adapt the host organism to its environment. This analysis illustrates how secondary structure predictions can assist evolutionary analyses, each important in "post-genomic" biochemistry.
journal_name
Proc Natl Acad Sci U S Aauthors
Tauer A,Benner SAdoi
10.1073/pnas.94.1.53subject
Has Abstractpub_date
1997-01-07 00:00:00pages
53-8issue
1eissn
0027-8424issn
1091-6490journal_volume
94pub_type
杂志文章abstract::The effect of pressure up to 175 kilobars on the electronic structure of three ferric hydroxamates and on ferrichrome A has been studied by optical absorption and Mössbauer resonance. The ferric ion was reduced to ferrous ion with pressure, as has been previously observed for various compounds. For the hydroxamates, 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.68.3.549
更新日期:1971-03-01 00:00:00
abstract::A 6.2-kb full-length clone encoding a distinct protein-tyrosine phosphatase (PTP; EC 3.1.3.48), PTPD1, was isolated from a human skeletal muscle cDNA library. The cDNA encodes a protein of 1174 amino acids with N-terminal sequence homology to the ezrin-band 4.1-merlin-radixin protein family, which also includes the tw...
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.91.16.7477
更新日期:1994-08-02 00:00:00
abstract::We investigated the influence of interareal distance on connectivity patterns in a database obtained from the injection of retrograde tracers in 29 areas distributed over six regions (occipital, temporal, parietal, frontal, prefrontal, and limbic). One-third of the 1,615 pathways projecting to the 29 target areas were...
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.1218972110
更新日期:2013-03-26 00:00:00
abstract::Analysis, by the recovery of specific genetic "markers," of the effects of DNase I, physical shear, and temperature shock on DNA-cell complexes demonstrates that sequential attachment of both ends of bacteriophage SP82G DNA to Bacillus subtilis precedes entry of the DNA molecule into the cell, and that each attachment...
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.69.6.1545
更新日期:1972-06-01 00:00:00
abstract::Evidence is presented that suggests that GTP (or 5'-guanylylmethylene diphosphonate) is not essential for either formation of an AUG-directed, initiation factor IF-2-dependent initiation complex on the 30S subunit or for positioning of fMet-tRNA on the peptidyl site. However, recycling of limiting amounts of IF-2 requ...
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.69.10.2770
更新日期:1972-10-01 00:00:00
abstract::Copper is a required metal nutrient for life, but global or local alterations in its homeostasis are linked to diseases spanning genetic and metabolic disorders to cancer and neurodegeneration. Technologies that enable longitudinal in vivo monitoring of dynamic copper pools can help meet the need to study the complex ...
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.1613628113
更新日期:2016-12-13 00:00:00
abstract::One goal of regenerative medicine is to repair damaged tissue. This requires not only generating new cells of the proper phenotype, but also selecting for those that properly integrate into sites of injury. In our laboratory we are using a cell-migration-based in vivo selection system to generate antibodies that induc...
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.1719259115
更新日期:2018-01-16 00:00:00
abstract::Understanding differences in DNA double-strand break (DSB) repair between tumor and normal tissues would provide a rationale for developing DNA repair-targeted cancer therapy. Here, using knock-in mouse models for measuring the efficiency of two DSB repair pathways, homologous recombination (HR) and nonhomologous end-...
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.2002917117
更新日期:2020-10-20 00:00:00
abstract::Some spectinomycin-resistant mutants of Escherichia coli are cold-sensitive. They are unable to assemble both 30S and 50S ribosomal subunits at low temperatures. They accumulate two kinds of incomplete particles, related to 30S and 50S subunits respectively. A single mutation, causing an alteration in a 30S ribosomal ...
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.67.3.1440
更新日期:1970-11-01 00:00:00
abstract::Seven morphologically nontransformed (flat) revertants with reduced tumorigenicity in vivo have been isolated from populations of Kirsten sarcoma virus-transformed NIH 3T3 cells transfected with a cDNA expression library of normal human fibroblasts. Each revertant harbors 1-10 recombinant plasmids per cell and retains...
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.86.1.162
更新日期:1989-01-01 00:00:00
abstract::Vaccine efficacy is determined largely by cellular and humoral immunity as well as long-lasting immunological memory. IL-2 and IL-15 were evaluated in vaccinia vectors expressing HIV gp160 for the establishment of an effective vaccine strategy. Both IL-2 and IL-15 in the vaccinia vector induced strong and long-lasting...
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.0630592100
更新日期:2003-03-18 00:00:00
abstract::Tuberculosis (TB) is a major public health problem. One-third of the world's population is estimated to be infected with Mycobacterium tuberculosis (MTB), the etiological agent causing TB, and active disease kills nearly 2 million individuals worldwide every year. Several lines of evidence indicate that interindividua...
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.1115761109
更新日期:2012-01-24 00:00:00
abstract::We have constructed bovine papilloma virus recombinants carrying a hybrid gene in which human growth hormone structural sequences are fused to the promoter and presumptive control region of the mouse metallothionein-I gene. Mouse cells transformed with the recombinants synthesize metallothionein-growth hormone hybrid ...
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.80.2.397
更新日期:1983-01-01 00:00:00
abstract::Human thioredoxin reductase (TR) contains selenocysteine (Secys) in a redox center [cysteine (Cys)-497,Secys-498] near the C-terminus. The essential role of Secys in TR isolated from HeLa cells was demonstrated by the alkylation studies. Reaction of native NADPH reduced enzyme with bromoacetate at pH 6.5 inhibited enz...
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.95.15.8520
更新日期:1998-07-21 00:00:00
abstract::The cDNA sequences encoding the adult alpha- and beta-globin polypeptides of a marsupial, the native cat Dasyurus viverrinus, have been cloned and their nucleotide sequences have been determined. Using these cDNA clones we have determined the chromosomal location of the native cat alpha- and beta-globin genes by in si...
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.82.23.8105
更新日期:1985-12-01 00:00:00
abstract::Dopaminergic and glutamatergic neurotransmissions in the striatum play an essential role in motor- and reward-related behaviors. Dysfunction of these neurotransmitter systems has been found in Parkinson's disease, schizophrenia, and drug addiction. Cyclin-dependent kinase 5 (CDK5) negatively regulates postsynaptic sig...
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.0308652100
更新日期:2004-02-17 00:00:00
abstract::We have developed a procedure for purifying highly specific polyclonal antibodies against 5-methylcytosine. These antibodies were used to probe the distribution of 5-methylcytosine among fractionated nucleosomes of mouse cell chromatin. Our results demonstrate that at least 80% of the 5-methylcytosine is localized 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.80.18.5490
更新日期:1983-09-01 00:00:00
abstract::Biological organisms have evolved a wide range of immune mechanisms to defend themselves against pathogens. Beyond molecular details, these mechanisms differ in how protection is acquired, processed, and passed on to subsequent generations-differences that may be essential to long-term survival. Here, we introduce a m...
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.1600663113
更新日期:2016-08-02 00:00:00
abstract::We have developed a cell-free system to study bacteriophage lambda DNA replication. Maximal DNA synthesis in vitro requires the four deoxynucleoside triphosphates, ATP, and exogenous lambda DNA. DNA synthesis requires the products of the phage O and P genes but is not inhibited by lambda repressor. The kinetics of syn...
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.71.5.1758
更新日期:1974-05-01 00:00:00
abstract::We developed two solid-phase reagent systems for microscopic visualization and characterization of melanocyte-stimulating hormone (MSH) receptors of melanoma cells. Multiple copies of [Nle-4,D-Phe-7]-alpha-MSH, a potent analog of alpha-MSH, were conjugated to microspheres (latex beads) or macrospheres (polyamide beads...
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.93.24.13715
更新日期:1996-11-26 00:00:00
abstract::The IgG2a monoclonal antibody TH-1, which reacts specifically with blood group A1 but with neither A2 nor O erythrocytes, has been established. The antibody reacted only with A1 erythrocytes in hemagglutination and antibody absorption assays; it did not react with A2 erythrocytes, even after trypsin or sialidase treat...
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.82.4.1199
更新日期:1985-02-01 00:00:00
abstract::The kappa-selective opioid peptide dynorphin A (DYN) inhibits neuronal adenylate cyclase activity and reduces neuronal voltage-dependent calcium currents. It is not yet known, however, whether the regulation of calcium channel activity is dependent on or independent of the adenylate cyclase/cAMP system. We used the wh...
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.87.18.7025
更新日期:1990-09-01 00:00:00
abstract::Pith parenchyma cells store water in various plant organs. These cells are especially important for producing sugar and ethanol from the sugar juice of grass stems. In many plants, the death of pith parenchyma cells reduces their stem water content. Previous studies proposed that a hypothetical D gene might be respons...
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.1807501115
更新日期:2018-09-11 00:00:00
abstract::Appropriate hematopoietic stem cell (HSC) self-renewal reflects the tight regulation of cell cycle entry and lineage commitment. Here, we show that Id1, a dominant-negative regulator of E protein transcription factors, maintains HSC self-renewal by preserving the undifferentiated state. Id1-deficient HSCs show increas...
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.0607894104
更新日期:2007-01-23 00:00:00
abstract::Less than 100 cis-regulatory DNAs have been characterized in the context of transgenic metazoan embryos. Here we investigate the feasibility of conducting a genome-wide search for tissue-specific enhancers in the ascidian Ciona intestinalis. A total of 138 random genomic DNA fragments with an average size of 1.7 kb we...
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.052024999
更新日期:2002-05-14 00:00:00
abstract::Peripheral blood leukocytes incubated with a semisynthetic phage antibody library and fluorochrome-labeled CD3 and CD20 antibodies were used to isolate human single-chain Fv antibodies specific for subsets of blood leukocytes by flow cytometry. Isolated phage antibodies showed exclusive binding to the subpopulation us...
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.92.9.3938
更新日期:1995-04-25 00:00:00
abstract::Here, using further optimized 3D culture that allows highly selective induction and long-term growth of human ES cell (hESC)-derived cortical neuroepithelium, we demonstrate unique aspects of self-organization in human neocorticogenesis. Self-organized cortical tissue spontaneously forms a polarity along the dorsocaud...
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.1315710110
更新日期:2013-12-10 00:00:00
abstract::We have constructed a hybrid E beta gene by replacing the second exon of the Ed beta gene (which encodes the majority of the beta 1 protein domain) with the corresponding exon from the Eb beta gene. The hybrid gene has been introduced into a d haplotype host, the lymphoma beta-cell line A20-2J, and an E alpha E beta d...
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.82.6.1678
更新日期:1985-03-01 00:00:00
abstract::Microorganisms modify rates and mechanisms of chemical and physical weathering and clay growth, thus playing fundamental roles in soil and sediment formation. Because processes in soils are inherently complex and difficult to study, we employ a model based on the lichen-mineral system to identify the fundamental inter...
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.96.7.3404
更新日期:1999-03-30 00:00:00
abstract::Golgi-associated cytoplasmic proteins, such as the coatomer protein complex, are required for vesicle budding and trafficking. We have previously described a cytoplasmic phosphoprotein, p200, which binds dynamically and specifically to Golgi membranes. The p200 protein is dissociated from Golgi membranes in the presen...
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.92.7.2874
更新日期:1995-03-28 00:00:00