Abstract:
:We report on the location of the chain part of the retinylidene chromophore in the projected density of bacteriorhodopsin as determined by neutron diffraction from the two-dimensional purple membrane lattice. For this purpose, partially deuterated retinal was synthesized containing 10 deuterons at positions C-8, C-10, C-12, C-14, C-19(3), and C-20(3) of the polyene chain. Two sets of dark-adapted samples were prepared in entirely different ways: (i) Deuterated retinal was incorporated biosynthetically during growth of the bacteria by using the mutant JW5, which is deficient in the synthesis of retinal. (ii) The chromophore was converted to retinal oxime, the resulting colorless apomembrane was regenerated with deuterated retinal, and the residual retinal oxime was removed by washing with bovine serum albumin. Characterization of these samples by x-ray diffraction, absorption, and flash spectroscopy showed that they were identical to native purple membrane samples as judged by these criteria. Fourier difference maps were calculated from the differences in inplane diffraction from the deuterated membranes and from protonated samples that were prepared in exactly the same way. At 8.7 A resolution, both maps show a single major peak at the same position with the center of mass of the labeled part of the chain (C-11) between helices 6 and 3 but closer to helix 6. It appears likely that the COOH-terminal helix G, to which retinal is attached at lysine-216, is either helix 2 or 6.
journal_name
Proc Natl Acad Sci U S Aauthors
Seiff F,Wallat I,Ermann P,Heyn MPdoi
10.1073/pnas.82.10.3227subject
Has Abstractpub_date
1985-05-01 00:00:00pages
3227-31issue
10eissn
0027-8424issn
1091-6490journal_volume
82pub_type
杂志文章abstract::We report free-standing atomic crystals that are strictly 2D and can be viewed as individual atomic planes pulled out of bulk crystals or as unrolled single-wall nanotubes. By using micromechanical cleavage, we have prepared and studied a variety of 2D crystals including single layers of boron nitride, graphite, sever...
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.0502848102
更新日期:2005-07-26 00:00:00
abstract::A two-component transposon system based on the Ac element of maize was used as a mutagen in Arabidopsis thaliana. Transposition of a Ds element marked with a hygromycin-resistance gene was activated from four different locations in the Arabidopsis genome. The progeny of 201 plants carrying independent transposition ev...
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.90.21.10370
更新日期:1993-11-01 00:00:00
abstract::Social insects are promising new models in aging research. Within single colonies, longevity differences of several magnitudes exist that can be found elsewhere only between different species. Reproducing queens (and, in termites, also kings) can live for several decades, whereas sterile workers often have a lifespan ...
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.1804046115
更新日期:2018-05-22 00:00:00
abstract::Most teenage fears subside with age, a change that may reflect brain maturation in the service of refined fear learning. Whereas adults clearly demarcate safe situations from real dangers, attenuating fear to the former but not the latter, adolescents' immaturity in prefrontal cortex function may limit their ability 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.1005494108
更新日期:2011-03-15 00:00:00
abstract::Infection by certain human papillomavirus types is regarded as the major risk factor in the development of cervical cancer, one of the most common cancers of women worldwide. Analysis of the immunogenic and structural features of papillomavirus virions has been hampered by the inability to efficiently propagate the vi...
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.89.24.12180
更新日期:1992-12-15 00:00:00
abstract::At least three separate regions of the Epstein-Barr virus (EBV) genome encode RNA in a cell line that is growth transformed and nonpermissively infected with EBV. Six polyadenylylated cytoplasmic RNAs have been identified from these three regions. An abundant RNA 3.0-3.1 kilobases (kb) long is encoded by DNA of the 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.78.3.1930
更新日期:1981-03-01 00:00:00
abstract::Timelapse video microscopy has been used to record the motility and dynamic interactions between an H-2Db-restricted murine cytotoxic T lymphocyte clone (F5) and Db-transfected L929 mouse fibroblasts (LDb) presenting normal or variant antigenic peptides from human influenza nucleoprotein. F5 cells will kill LDb target...
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.95.26.15571
更新日期:1998-12-22 00:00:00
abstract::The structure of the non-self-complementary DNA heptamer d(CGACGAC) at low pH has been determined by the quantitative NMR refinement procedure designated SPEDREF (SPEctral-Driven REFinement). Acid-base titration of the molecule indicated a prominent n = 2 pKa near 6.8. In the pH range up to 6.0, the heptamer forms a r...
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.90.11.5224
更新日期:1993-06-01 00:00:00
abstract::Arteriovenous (AV) malformation (AVM) is a devastating condition characterized by focal lesions of enlarged, tangled vessels that shunt blood from arteries directly to veins. AVMs can form anywhere in the body and can cause debilitating ischemia and life-threatening hemorrhagic stroke. The mechanisms that underlie AVM...
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.1415316111
更新日期:2014-12-16 00:00:00
abstract::Leptin is a pivotal regulator of energy and glucose homeostasis, and defects in leptin signaling result in obesity and diabetes. The ATP-sensitive potassium (K(ATP)) channels couple glucose metabolism to insulin secretion in pancreatic β-cells. In this study, we provide evidence that leptin modulates pancreatic β-cell...
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.1216351110
更新日期:2013-07-30 00:00:00
abstract::The secreted nodulation-signaling protein NodO was purified from the supernatant of cultures of Rhizobium leguminosarum biovar viciae. The native protein has a M(r) of approximately 67,000, suggesting that it exists as a dimer since the DNA sequence predicts a M(r) of 30,002. Pure NodO protein had no protease, pectina...
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.91.21.9990
更新日期:1994-10-11 00:00:00
abstract::Magnetic interactions between dissolved oxygen and nitroxide radical spin probes lead to broadening of the ESR lines. We have used a closed-chamber method based on this property to determine the maximum rate of O2 uptake per cell (Vmax per cell) in cultured mammalian cells. A suitable spin probe and a cell suspension ...
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.79.4.1166
更新日期:1982-02-01 00:00:00
abstract::The genetic coupling hypothesis of signal-preference evolution, whereby the same genes control male signal and female preference for that signal, was first inspired by the evolution of cricket acoustic communication nearly 50 years ago. To examine this hypothesis, we compared the genomic location of quantitative trait...
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.0900229106
更新日期:2009-06-16 00:00:00
abstract::Protein-binding DNA sequence elements encode a variety of regulated functions of genomes. Information about such elements is currently in a state of rapid growth, but improved methods are required to characterize the sequence specificity of DNA-binding proteins. We have established an in vitro method for specific and ...
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.0611229104
更新日期:2007-02-27 00:00:00
abstract::Translation of injected mRNA in oocytes of Xenopus laevis has been used as a highly sensitive and quantitative assay for interferon mRNA. Injection into oocytes of polyadenylylated RNA extracted from poly(I).poly(C)-induced human diploid fibroblasts (FS-4) leads to the synthesis of biologically active human fibroblast...
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.74.8.3409
更新日期:1977-08-01 00:00:00
abstract::Neurons respond to sensory stimuli by altering the rate and temporal pattern of action potentials. These spike trains both encode and propagate information that guides behavior. Local inhibitory networks can affect the information encoded and propagated by neurons by altering correlations between different spike train...
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.1015165108
更新日期:2011-04-05 00:00:00
abstract::The DNA of the attenuator region of the histidine operon of Escherichia coli has been transcribed in a purified in vitro system and found to synthesize two major RNA transcripts. The first one, 180 nucleotides long, has been identified as the histidine-specific leader RNA. It contains the coding sequence for the leade...
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.78.5.2767
更新日期:1981-05-01 00:00:00
abstract::Inwardly rectifying potassium (K(+)) channels gated by G proteins (Kir3.x family) are widely distributed in neuronal, atrial, and endocrine tissues and play key roles in generating late inhibitory postsynaptic potentials, slowing the heart rate and modulating hormone release. They are directly activated by G(betagamma...
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.080572297
更新日期:2000-05-09 00:00:00
abstract::During the late Pleistocene, early anatomically modern humans coexisted in Europe with the anatomically archaic Neandertals for some thousand years. Under the recent variants of the multiregional model of human evolution, modern and archaic forms were different but related populations within a single evolving species,...
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.1130343100
更新日期:2003-05-27 00:00:00
abstract::Human skin and lung mast cells and rodent peritoneal mast cells contain a carboxypeptidase in their secretory granules. We have screened human lung cDNA libraries with a mouse mast cell carboxypeptidase A (MC-CPA) cDNA probe to isolate a near-full-length cDNA that encodes human MC-CPA. The 5' end of the human MC-CPA 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.86.23.9480
更新日期:1989-12-01 00:00:00
abstract::The highly homologous Rnf2 (Ring1b) and Ring1 (Ring1a) proteins were identified as in vivo interactors of the Polycomb Group (PcG) protein Bmi1. Functional ablation of Rnf2 results in gastrulation arrest, in contrast to relatively mild phenotypes in most other PcG gene null mutants belonging to the same functional gro...
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.0434312100
更新日期:2003-03-04 00:00:00
abstract::The subcellular localization of cathepsin B activity (EC 3.4.22.1) in three murine melanomas of increasing metastatic potential (Cloudman less than B16-F1 less than B16 amelanotic) was determined. Cathepsin B activity was localized in the heavy mitochondrial fraction of normal murine liver but in the light mitochondri...
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.83.8.2483
更新日期:1986-04-01 00:00:00
abstract::Nociceptive information is modulated by a large number of endogenous signaling agents that change over the course of recovery from injury. This plasticity makes understanding regulatory mechanisms involved in descending inhibition of pain scientifically and clinically important. Neurons that synthesize the neuropeptid...
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.1306342110
更新日期:2013-08-06 00:00:00
abstract::CD95 type I and II cells differ in their dependence on mitochondria to execute apoptosis, because antiapoptotic members of the Bcl-2 family render only type II cells resistant to death receptor-induced apoptosis. They can also be distinguished by a more efficient formation of the death-inducing signaling complex in ty...
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.2034995100
更新日期:2003-09-30 00:00:00
abstract::The shape of a plant is largely determined by regulation of lateral branching. Branching architecture can vary widely in response to both genotype and environment, suggesting regulation by a complex interaction of autonomous genetic factors and external signals. Tillers, branches initiated at the base of grass plants,...
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.1102819108
更新日期:2011-08-16 00:00:00
abstract::Recent evidence suggests that the microbial community in the human intestine may play an important role in the pathogenesis of obesity. We examined 184,094 sequences of microbial 16S rRNA genes from PCR amplicons by using the 454 pyrosequencing technology to compare the microbial community structures of 9 individuals,...
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.0812600106
更新日期:2009-02-17 00:00:00
abstract::Low density lipoprotein (LDL) isolated from human plasma anticoagulated with EDTA (EDTA/LDL) was 4-fold more resistant to oxidation by reagent H2O2, as assayed by the thiobarbituric acid (TBA) assay, than LDL prepared from plasma anticoagulated with citrate (CDP/LDL). The LDLs required 1-3 mM H2O2 for maximal oxidatio...
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.83.17.6631
更新日期:1986-09-01 00:00:00
abstract::Thymic epithelial cells (TECs), the major component of the thymic microenvironment, can be modulated by pituitary hormones. We have shown previously that prolactin (PRL) can influence the endocrine activity of TECs and stimulate TEC proliferation as well as cytokeratin expression, suggesting the existence of PRL recep...
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.88.21.9700
更新日期:1991-11-01 00:00:00
abstract::Mutant, but not wild-type p53 binds with high affinity to a variety of MAR-DNA elements (MARs), suggesting that MAR-binding of mutant p53 relates to the dominant-oncogenic activities proposed for mutant p53. MARs recognized by mutant p53 share AT richness and contain variations of an AATATATTT "DNA-unwinding motif," 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.95.23.13681
更新日期:1998-11-10 00:00:00
abstract::AB5 bacterial toxins and polyomaviruses induce membrane curvature as a mechanism to facilitate their entry into host cells. How membrane bending is accomplished is not yet fully understood but has been linked to the simultaneous binding of the pentameric B subunit to multiple copies of glycosphingolipid receptors. Her...
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.2001119117
更新日期:2020-06-30 00:00:00