Abstract:
:Enzyme rates are usually considered to be dependent on local properties of the molecules involved in reactions. However, for large molecules, distant constraints might affect reaction rates by affecting dynamics leading to transition states. In single-molecule experiments we have found that enzymes that relax DNA torsional stress display rates that depend strongly on how the distant ends of the molecule are constrained; experiments with different-sized particles tethered to the end of 10-kb DNAs reveal enzyme rates inversely correlated with particle drag coefficients. This effect can be understood in terms of the coupling between molecule extension and local molecular stresses: The rate of bead thermal motion controls the rate at which transition states are visited in the middle of a long DNA. Importantly, we have also observed this effect for reactions on unsupercoiled DNA; other enzymes show rates unaffected by bead size. Our results reveal a unique mechanism through which enzyme rates can be controlled by constraints on macromolecular or supramolecular substrates.
journal_name
Proc Natl Acad Sci U S Aauthors
Bai H,Kath JE,Zörgiebel FM,Sun M,Ghosh P,Hatfull GF,Grindley ND,Marko JFdoi
10.1073/pnas.1203118109subject
Has Abstractpub_date
2012-10-09 00:00:00pages
16546-51issue
41eissn
0027-8424issn
1091-6490pii
1203118109journal_volume
109pub_type
杂志文章abstract::The effect of metabolic depletion on the maturation-associated loss of membrane functions has been studied by using sheep reticulocytes incubated in vitro at 37 degrees C for periods up to 41 hr. ATP was either maintained with glucose, adenosine plus inosine, or depleted with 2-deoxyglucose plus arsenate. Two membrane...
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.80.16.4978
更新日期:1983-08-01 00:00:00
abstract::Proteolipid protein (PLP) is the major myelin membrane protein of the central nervous system. We have isolated a copy of an alternatively spliced PLP gene transcript from a mouse brain cDNA library that was screened for PLP-related sequences. The encoded 241-amino acid protein differs from PLP by an internal deletion ...
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.84.16.5665
更新日期:1987-08-01 00:00:00
abstract::A discrepancy is explored regarding the spin exchange integral estimated from magnetic field effects on recombination of the bacteriochlorophyll dimer cation (Bchl)(2)+ and the bacteriopheophytin anion Bph(-) and the measured electron transfer rate between Bph and electronically excited (Bchl)(2). In one explanation 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.76.9.4185
更新日期:1979-09-01 00:00:00
abstract::Using tunicamycin, we have investigated the role of glycoproteins in membrane transport. Tunicamycin is a glucosamine-containing antibiotic that specifically inhibits dolichol pyrophosphate-mediated glycosylation of asparaginyl residues of glycoproteins. Inhibition of protein glycosylation in chick embryo fibroblasts ...
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.76.2.791
更新日期:1979-02-01 00:00:00
abstract::The major histocompatibility complex-encoded class I molecule, a noncovalent dimer of a polymorphic 45-kDa heavy chain and a nonpolymorphic 12-kDa beta 2-microglobulin (beta 2m) light chain, binds peptide antigen prior to its interaction with T-cell antigen receptors. We report here that the binding in aqueous solutio...
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.89.6.2242
更新日期:1992-03-15 00:00:00
abstract::Cross-talk between the microtubule and actin networks has come under intense scrutiny following the realization that it is crucial for numerous essential processes, ranging from cytokinesis to cell migration. It is becoming increasingly clear that proteins long-considered highly specific for one or the other cytoskele...
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.1917964117
更新日期:2020-02-25 00:00:00
abstract::Specific [3H]retinoic acid (RA)-binding sites in nuclear and cytosolic extracts prepared from human myeloblastic leukemia HL-60 cells have been detected by sucrose density gradient sedimentation and size-exclusion high-performance liquid chromatography (HPLC) analyses. This RA-binding activity migrated as a single pea...
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.86.15.5854
更新日期:1989-08-01 00:00:00
abstract::Identifying presynaptic mechanisms of general anesthetics is critical to understanding their effects on synaptic transmission. We show that the volatile anesthetic isoflurane inhibits synaptic vesicle (SV) exocytosis at nerve terminals in dissociated rat hippocampal neurons through inhibition of presynaptic Ca(2+) inf...
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.1500525112
更新日期:2015-09-22 00:00:00
abstract::Cdc7 is an essential kinase required for the initiation of eukaryotic DNA replication. Previous studies in many species showed that the minichromosome maintenance complex is a major physiological target of this kinase. In this study, we have mapped the sites in human Mcm2 protein that are phosphorylated by Cdc7. The i...
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.0604990103
更新日期:2006-08-01 00:00:00
abstract::The colony-stimulating factors (CSFs) greatly influence mature macrophage function in vitro: macrophage (M)-CSF induces maturation of monocytes and enhances differentiated cell function; granulocyte-macrophage (GM)-CSF stimulates a variety of antimicrobial functions. In vivo M-CSF is thought to promote differentiation...
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.90.6.2517
更新日期:1993-03-15 00:00:00
abstract::This paper shows that the most predictable components of internal variability in coupled atmosphere-ocean models are remarkably similar to the most predictable components of climate models without interactive ocean dynamics (i.e., models whose ocean is represented by a 50-m-deep slab ocean mixed layer with no interact...
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.1614085114
更新日期:2017-02-28 00:00:00
abstract::In liquids realm, surface tension and capillarity are the key forces driving the formation of the shapes pervading the nature. The steady dew drops appearing on plant leaves and spider webs result from the minimization of the overall surface energy [Zheng Y, et al. (2010) Nature 463:640-643]. Thanks to the surface ten...
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.1110676108
更新日期:2011-09-13 00:00:00
abstract::Multiple sclerosis is a chronic disease of the central nervous system (CNS) characterized by inflammation, demyelination, and axonal loss. The immunopathogenesis of demyelination in multiple sclerosis involves an autoantibody response to myelin oligodendrocyte glycoprotein (MOG), a type I transmembrane protein located...
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.1133443100
更新日期:2003-08-05 00:00:00
abstract::Ventilator-induced diaphragmatic dysfunction (VIDD) refers to the diaphragm muscle weakness that occurs following prolonged controlled mechanical ventilation (MV). The presence of VIDD impedes recovery from respiratory failure. However, the pathophysiological mechanisms accounting for VIDD are still not fully understo...
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.1609707113
更新日期:2016-08-09 00:00:00
abstract::Yeast RNA polymerase II initiation factor e was purified to homogeneity and identified by biochemical criteria as the counterpart of human transcription factor IIB. Factor e was essential for initiation of transcription from yeast and mammalian promoters in a reconstituted yeast transcription system. Activity resided ...
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.89.23.11292
更新日期:1992-12-01 00:00:00
abstract::A detailed single-crystal X-ray study of conformationally flexible sulfonimide-based dendritic molecules with systematically varied molecular architectures was undertaken. Thirteen crystal structures reported in this work include 9 structures of the second-generation dendritic sulfonimides decorated with different ary...
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.0904264106
更新日期:2009-07-07 00:00:00
abstract::Monoclonal antibodies were used to isolate nonneutralizable antigenic variants in the hemagglutinin-neuraminidase glycoprotein of Newcastle disease virus. It had been found that a large percentage of virus retains infectivity despite binding neutralizing antibody. This high persistent fraction of nonneutralized virus ...
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.82.20.7106
更新日期:1985-10-01 00:00:00
abstract::Electrical stimulation of the cervical vagus nerve in anesthetized guinea pigs induced a rapid increase in respiratory insufflation pressure, suggesting increased airway resistance. After intravenous administration of a substance P (SP) antagonist, [D-Arg(1),D-Pro(2),D-Trp(7,9),Leu(11)]SP, the insufflation pressure re...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1983-02-01 00:00:00
abstract::The economic and ecological costs of wildfire in the United States have risen substantially in recent decades. Although climate change has likely enabled a portion of the increase in wildfire activity, the direct role of people in increasing wildfire activity has been largely overlooked. We evaluate over 1.5 million g...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2017-03-14 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章,随机对照试验
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更新日期:2008-02-05 00:00:00
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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.80.20.6234
更新日期:1983-10-01 00:00:00
abstract::The amplitude of the CO(2) seasonal cycle at the Mauna Loa Observatory (MLO) increased from the early 1970s to the early 1990s but decreased thereafter despite continued warming over northern continents. Because of its location relative to the large-scale atmospheric circulation, the MLO receives mainly Eurasian air m...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2007-03-13 00:00:00
abstract::How granzymes gain entry into the cytosol of target cells during killer cell attack has been the subject of several studies in the past, but the effective delivery mechanism during target cell encounter has not been clarified. Here we show that granzyme B (GzmB) mutants lacking binding to negatively charged, essential...
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.0801724105
更新日期:2008-09-16 00:00:00
abstract::Previous studies have shown that defective virus vectors (amplicons) derived from herpes simplex viruses could be efficiently propagated in virus stocks in the presence of trans-acting helper virus functions. The present study established that two separate cis-acting functions--a DNA replication origin and a cleavage/...
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.82.3.694
更新日期:1985-02-01 00:00:00
abstract::The spatial extent of the cortical filters selective for different spatial frequencies and orientations is limited. We studied psychophysically how information from the local filters is integrated into global pattern shapes, i.e., whether performance in the identification of a global pattern consisting of small, local...
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.94.15.8267
更新日期:1997-07-22 00:00:00
abstract::When purified dimers of hemagglutinin-neuraminidase molecules released by protease digestion from three strains of human parainfluenza virus 1 were used in crystallization trials, long thin needle crystals formed. Electron microscopic analysis of these needle crystals revealed that they are composed of stacks of tripl...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.90.4.1523
更新日期:1993-02-15 00:00:00
abstract::Assembly of light-harvesting complexes requires synchronization of chlorophyll (Chl) biosynthesis with biogenesis of light-harvesting Chl a/b-binding proteins (LHCPs). The chloroplast signal recognition particle (cpSRP) pathway is responsible for transport of nucleus-encoded LHCPs in the stroma of the plastid and thei...
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.1719645115
更新日期:2018-04-10 00:00:00
abstract::Two deletion-substitution mutations of phage lambda, spi-113 and spi-274, are shown to remove about half of the rightward operator OR. Physiological studies show that spi-113 is still repressible. Thus, the 50 or so nucleotides of OR deleted in this mutant are not absolutely essential for repression. prm-116, which 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.73.3.712
更新日期:1976-03-01 00:00:00
abstract::Inactivation of the transcription factor p53 is central to carcinogenesis. Yet only approximately one-half of cancers have p53 loss-of-function mutations. Here, we demonstrate a mechanism for p53 inactivation by apoptosis repressor with caspase recruitment domain (ARC), a protein induced in multiple cancer cells. 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.0710017104
更新日期:2007-12-26 00:00:00
abstract::1-Aminocyclopropane-1-carboxylate (ACC) synthase (EC 4.4.1.14), extracted from tomato pericarp tissue, was purified 6500-fold by conventional and high-performance liquid chromatography. Two-dimensional gel electrophoresis of this preparation indicated that ACC synthase activity was associated with a protein band at 50...
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.83.20.7755
更新日期:1986-10-01 00:00:00