Abstract:
:The dissociation and association of an immobilized preparation of the octameric enzyme porphobilinogen synthase [5-aminolevulinate hydro-lyase (adding 5-aminolevulinate and cyclizing), EC 4.2.1.24] is described. On treatment of the immobilized preparation with 4 M urea, four subunits per octamer are removed which can be reassociated into a soluble octameric enzyme. The tetrameric bound residual protein can also be reassembled into an octameric structure, with the same initial enzyme activity, by exposing the residual bound protein to a soluble pure enzyme preparation or to a crude liver extract in the presence of urea. The dissociation of the reconstituted bound enzyme releases subunits that again can be reassembled into a soluble octameric pure protein even when the crude liver preparation is used as the donor of the subunits. Thus, a pure enzyme can be isolated in a reassociation-dissociation cycle. The use of immobilized preparations of oligomeric proteins is considered for intra- and interspecies hybridization studies and for the ready preparation of purified enzyme preparations from different species and is suggested as a model for study of the formation of an oligomeric enzyme in the presence of other polypeptides.
journal_name
Proc Natl Acad Sci U S Aauthors
Gurne D,Chen J,Shemin Ddoi
10.1073/pnas.74.4.1383subject
Has Abstractpub_date
1977-04-01 00:00:00pages
1383-7issue
4eissn
0027-8424issn
1091-6490journal_volume
74pub_type
杂志文章abstract::Mechanisms for controlling symbiont populations are critical for maintaining the associations that exist between a host and its microbial partners. We describe here the transcriptional, metabolic, and ultrastructural characteristics of a diel rhythm that occurs in the symbiosis between the squid Euprymna scolopes 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.0909712107
更新日期:2010-02-02 00:00:00
abstract::Phytoplankton often encounter turbulence in their habitat. As most toxic phytoplankton species are motile, resolving the interplay of motility and turbulence has fundamental repercussions on our understanding of their own ecology and of the entire ecosystems they inhabit. The spatial distribution of motile phytoplankt...
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.1808711115
更新日期:2018-11-27 00:00:00
abstract::Glucagon-like peptide-1 (GLP-1), released from gut endocrine L cells in response to glucose, regulates appetite, insulin secretion, and gut motility. How glucose given orally, but not systemically, induces GLP-1 secretion is unknown. We show that human duodenal L cells express sweet taste receptors, the taste G protei...
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.0706890104
更新日期:2007-09-18 00:00:00
abstract::We have tested the effect of increased ribosomal fidelity on a modified version of the programmed release factor 2 (RF2) translational frameshift. In the constructs tested, the original UGA codon at the site of the shift was replaced by either of two sense codons, UGG (tryptophan), which allows a frameshift of approxi...
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.90.6.2315
更新日期:1993-03-15 00:00:00
abstract::Bcl-2 family proteins play a crucial role in tissue homeostasis and apoptosis (programmed cell death). Bid is a proapoptotic member of the Bcl-2 family, promoting cell death when activated by caspase-8. Following an NMR-based approach (structure-activity relationships by interligand NOE) we were able to identify two 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.0603460103
更新日期:2006-08-15 00:00:00
abstract::The kinetics for hydrogen exchange at individual base pairs in self-complementary deoxydodecanucleotide duplexes have been estimated from NMR saturation recovery measurements on the resolved imino protons as a function of temperature. The imino protons of dA . dT base pairs in the center of the fully alternating d(C-G...
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.80.8.2184
更新日期:1983-04-01 00:00:00
abstract::We have reexamined the balance between cell birth, cell maturation, and cell death in the thymus by labeling dividing thymocytes and their progeny in vivo with [3H]-thymidine, isolating clearly defined subpopulations by fluorescence-activated cell sorting, and determining the distribution of label by autoradiography. ...
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.87.7.2579
更新日期:1990-04-01 00:00:00
abstract::Bones of the flightless sea duck (Chendytes lawi) from 14 archaeological sites along the California coast indicate that humans hunted the species for at least 8,000 years before it was driven to extinction. Direct (14)C dates on Chendytes bones show that the duck was exploited on the southern California islands as ear...
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.0711140105
更新日期:2008-03-18 00:00:00
abstract::We have determined the complete primary structure of human hemopexin, a plasma beta-glycoprotein that specifically binds one heme with high affinity and transports it to hepatocytes for salvage of the iron. Human hemopexin (Mr approximately equal to 63,000) consists of a single polypeptide chain containing 439 amino a...
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.82.1.73
更新日期:1985-01-01 00:00:00
abstract::We describe two collaborations in which psychologists and economists provided essential support on foundational projects in major research programs. One project involved eliciting adolescents' expectations regarding significant future life events affecting their psychological and economic development. The second proje...
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.1615461114
更新日期:2017-03-28 00:00:00
abstract::Peace River is one of the few shocked members of the L-chondrites clan that contains both high-pressure polymorphs of olivine, ringwoodite and wadsleyite, in diverse textures and settings in fragments entrained in shock-melt veins. Among these settings are complete olivine porphyritic chondrules. We encountered few sq...
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.0801518105
更新日期:2008-06-24 00:00:00
abstract::The cis-acting regulatory sequence of transcription from long terminal repeats (LTRs) of human T-cell leukemia virus type I and type II (HTLV-I and HTLV-II), which is essential for action of the virally encoded trans-acting transcriptional factor(s) designated pX(s), in HTLV-I and -II was identified. Deletion of most ...
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.83.21.8112
更新日期:1986-11-01 00:00:00
abstract::A predictive coarse-grained protein force field [associative memory, water-mediated, structure, and energy model for molecular dynamics (AWSEM)-MD] is used to study the energy landscapes and relative stabilities of amyloid-β protein (1-40) in the monomer and all of its oligomeric forms up to an octamer. We find that a...
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.1612362113
更新日期:2016-10-18 00:00:00
abstract::Protein Hal is a human gamma4 heavy-chain disease protein whose molecular weight is reduced from 55,000 to 25,000 in 6 M guanidine due to the lack of disulfide bonds between heavy chains. Studies of aminoacid sequence indicate that it contains a gap of about 240 residues, starting 10 residues from the N-terminal end a...
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.70.4.1073
更新日期:1973-04-01 00:00:00
abstract::The complete amino acid sequence of Xenopus laevis nonmuscle myosin heavy chain B (MHC-B) has been deduced from overlapping cDNA clones isolated from an XTC cell library. RNA blots of various developmental stages, adult tissues, and XTC cells detect a single transcript of 7.5 kb which is expressed at similar levels th...
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.90.7.2856
更新日期:1993-04-01 00:00:00
abstract::Single-nucleotide polymorphisms (SNPs) in the human ether-a-go-go-related gene 1, hERG1, are associated with cardiac arrhythmias. The Kv11.1 channels encoded by hERG1 are also essential for rhythmic excitability of the pituitary, where they are regulated by thyroid hormone through a signal transduction cascade involvi...
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.0802250105
更新日期:2008-09-23 00:00:00
abstract::Gene delivery to skeletal muscle is a promising strategy for the treatment of muscle disorders and for the systemic secretion of therapeutic proteins. However, present DNA delivery technologies have to be improved with regard to both the level of expression and interindividual variability. We report very efficient pla...
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.96.8.4262
更新日期:1999-04-13 00:00:00
abstract::Recent findings intriguingly place DNA double-strand break repair proteins at chromosome ends in yeast, where they help maintain normal telomere length and structure. In the present study, an essential telomere function, the ability to cap and thereby protect chromosomes from end-to-end fusions, was assessed in repair...
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.96.26.14899
更新日期:1999-12-21 00:00:00
abstract::Fatty acylation of cysteine residues provides spatial and temporal control of protein function in cells and regulates important biological pathways in eukaryotes. Although recent methods have improved the detection and proteomic analysis of cysteine fatty (S-fatty) acylated proteins, understanding how specific sites a...
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.1602244113
更新日期:2016-04-19 00:00:00
abstract::A7r5 smooth muscle (aorta) cells have a spontaneous electrical activity. Application of vasopressin produces a hyperpolarization accompanied by an interruption of the spontaneous activity, which is followed by a depolarization associated with a recovery of the spiking activity. Vasopressin action is produced by an act...
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.85.23.9365
更新日期:1988-12-01 00:00:00
abstract::Perhydrohistrionicotoxin, at concentrations of 10(-12)-10(-7) M, depressed the current generated by iontophoretic application of acetylcholine to endplate regions of soleus and extensor digitorum longus muscles of rats. However, no changes in the amplitude or time course of spontaneous miniature endplate potentials or...
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.75.3.1596
更新日期:1978-03-01 00:00:00
abstract::Proteins of plant cell walls serve as structural macromolecules and play important roles in morphogenesis and development but have not been reported to be the origins of peptide signals that activate genes for plant defense. We report here that the mRNA coding the tomato leaf polyprotein precursor of three hydroxyprol...
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.0505248102
更新日期:2005-09-06 00:00:00
abstract::Biological processes often require that a single gene product participate in multiple types of molecular interactions. Viruses with quasiequivalent capsids provide an excellent paradigm for studying such phenomena because identical protein subunits are found in different structural environments. Differences in subunit...
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.93.1.27
更新日期:1996-01-09 00:00:00
abstract::ChIP coupled with microarray provides a powerful tool to determine in vivo binding profiling of transcription factors to deduce regulatory circuitries in mammalian cells. Aiming at improving the specificity and sensitivity of such analysis, we developed a new technology called ChIP-DSL using the DNA selection and liga...
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.0700715104
更新日期:2007-03-20 00:00:00
abstract::To identify proteins that regulate the transcriptional activity of c-Jun, we have used the yeast two-hybrid screen to detect mammalian polypeptides that might interact functionally with the N-terminal segment of c-Jun, a known regulatory region. Among the proteins identified is a short form of Stat3 (designated Stat3 ...
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.92.20.9097
更新日期:1995-09-26 00:00:00
abstract::Normal rat kidney cells were nonproductively infected either with CP27, a mutant of Moloney sarcoma virus that is temperature-sensitive for maintenance of transformation, or with the parental wild-type virus. The nonproducer cells were inoculated into the tails of athymic nude mice that were subsequently incubated at ...
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.77.3.1501
更新日期:1980-03-01 00:00:00
abstract::A critical step in neuronal development is the formation of axon/dendrite polarity, a process involving symmetry breaking in the newborn neuron. Local self-amplifying processes could enhance and stabilize the initial asymmetry in the distribution of axon/dendrite determinants, but the identity of these processes remai...
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.1115907108
更新日期:2011-11-08 00:00:00
abstract::Type I interferons (IFNs) are helical cytokines that have diverse biological activities despite the fact that they appear to interact with the same receptor system. To achieve a better understanding of the structural basis for the different activities of alpha and beta IFNs, we have determined the crystal structure of...
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.94.22.11813
更新日期:1997-10-28 00:00:00
abstract::Noncatalytic carbohydrate binding modules (CBMs) are components of glycoside hydrolases that attack generally inaccessible substrates. CBMs mediate a two- to fivefold elevation in the activity of endo-acting enzymes, likely through increasing the concentration of the appended enzymes in the vicinity of the substrate. ...
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.1212034109
更新日期:2012-12-18 00:00:00
abstract::Adenosine 3':5'-cyclic monophosphate (cAMP) and guanosine 3':5'-cyclic monophosphate (cGMP) were localized in cells of rat kidney cortex by an immunocytochemical technique before and after perfusion with parathyroid hormone (PTH). In control tissues the cAMP antiserum detected approximately the same intensity of fluor...
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.74.8.3569
更新日期:1977-08-01 00:00:00