Abstract:
:The metal-binding motif in the sequence of leukotriene A4 (LTA4) (EC 3.3.2.6), a bifunctional zinc metalloenzyme, contains a glutamic acid that is conserved in several zinc hydrolases. To study its role for the two catalytic activities, Glu-296 in mouse leukotriene A4 hydrolase was replaced by a glutamine or alanine residue by site-directed mutagenesis. Wild-type and mutated cDNAs were expressed four or five times in Escherichia coli, and the resulting proteins were purified to apparent homogeneity. With respect to their epoxide hydrolase activities--i.e., the conversion of LTA4 into leukotriene B4--the mutated enzymes [Gln296]LTA4 hydrolase and [Ala296]LTA4 hydrolase exhibited specific activities of 1070 +/- 160 and 90 +/- 30 nmol of LTB4 per mg of protein per min (mean +/- SD; n = 4 or 5), respectively, corresponding to 150% and 15% of unmutated enzyme. In contrast, when the mutated proteins were assayed for peptidase activity toward alanine-4-nitroanilide, they were found to be virtually inactive (less than or equal to 0.2% of unmutated enzyme). To serve as a positive control, we also replaced Ser-298 with an alanine residue, which resulted in a protein ([Ala298]LTA4 hydrolase) with catalytic properties almost indistinguishable from the wild-type enzyme. Substitution of Glu-296 by glutamine or alanine was also carried out with human LTA4 hydrolase, and the mutated human enzymes displayed specific activities similar to the corresponding mouse proteins. Zinc analyses of the purified mouse and human proteins confirmed that the mutations did not significantly influence their zinc content. In conclusion, the results of the present study indicate a direct catalytic role for Glu-296 in the peptidase reaction of LTA4 hydrolase, where it presumably acts as a base to polarize water, whereas its function, if any, is apparently not essential in the epoxide hydrolase reaction.
journal_name
Proc Natl Acad Sci U S Aauthors
Wetterholm A,Medina JF,Rådmark O,Shapiro R,Haeggström JZ,Vallee BL,Samuelsson Bdoi
10.1073/pnas.89.19.9141keywords:
subject
Has Abstractpub_date
1992-10-01 00:00:00pages
9141-5issue
19eissn
0027-8424issn
1091-6490journal_volume
89pub_type
杂志文章abstract::Local changes in conformation between the calcium-saturated and calcium-free forms of calmodulin were monitored using antisera to four peptides corresponding to three helical regions of the calcium-saturated protein. The N-terminal helix was monitored using antiserum to residues 9-19, calmodulin-(9-19); the C-terminal...
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.83.23.8888
更新日期:1986-12-01 00:00:00
abstract::Cold-water conditions have excluded durophagous (skeleton-breaking) predators from the Antarctic seafloor for millions of years. Rapidly warming seas off the western Antarctic Peninsula could now facilitate their return to the continental shelf, with profound consequences for the endemic fauna. Among the likely first ...
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.1513962112
更新日期:2015-10-20 00:00:00
abstract::In movies or on TV, a wheel can seem to rotate backwards, due to the temporal subsampling inherent in the recording process (the wagon wheel illusion). Surprisingly, this effect has also been reported under continuous light, suggesting that our visual system, too, might sample motion in discrete "snapshots." Recently,...
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.0409172102
更新日期:2005-04-05 00:00:00
abstract::Plant cuticles are composed of wax and cutin and evolved in the land plants as a hydrophobic boundary that reduces water loss from the plant epidermis. The expanding maize adult leaf displays a dynamic, proximodistal gradient of cuticle development, from the leaf base to the tip. Laser microdissection RNA Sequencing (...
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.2004945117
更新日期:2020-06-02 00:00:00
abstract::An investigation by paramagnetic resonance spectroscopy of the photoreduction of ferredoxin, oxygenically by water and anoxygenically by a direct electron donor to photosystem I, led to the unexpected findings that different reductive mechanisms may be involved. Ferredoxin photoreduced by water was not reoxidized in 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.77.5.2676
更新日期:1980-05-01 00:00:00
abstract::Animal mitochondrial DNA (mtDNA) maintains a displacement loop (D loop) at the heavy strand origin of replication. These D loops represent sharply limited synthesis of heavy strands and provide a unique opportunity to examine the termination of DNA synthesis. Direct sizing at the nucleotide level indicates that the 3'...
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.78.10.6116
更新日期:1981-10-01 00:00:00
abstract::Recent studies have suggested that Paleozoic hyperoxia enabled animal gigantism, and the subsequent hypoxia drove a reduction in animal size. This evolutionary hypothesis depends on the argument that gas exchange in many invertebrates and skin-breathing vertebrates becomes compromised at large sizes because of distanc...
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.0611544104
更新日期:2007-08-07 00:00:00
abstract::Helping and sharing among humans is often motivated by empathy and accompanied by a sense of satisfaction. To determine whether similar self-rewarding mechanisms may underpin assistance among nonhuman primates, eight female brown capuchin monkeys (Cebus apella) underwent testing in a simple choice paradigm. Paired wit...
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.0807060105
更新日期:2008-09-09 00:00:00
abstract::Ancient societies are often used to illustrate the potential problems stemming from unsustainable land-use practices because the past seems rife with examples of sociopolitical "collapse" associated with the exhaustion of finite resources. Just as frequently, and typically in response to such presentations, archaeolog...
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.1409646111
更新日期:2014-08-12 00:00:00
abstract::Cell-based therapies are attractive for revascularizing and regenerating tissues and organs, but clinical trials of endothelial progenitor cell transplantation have not resulted in consistent benefit. We propose a different approach in which a material delivery system is used to create a depot of vascular progenitor 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.0803873105
更新日期:2008-09-23 00:00:00
abstract::The major protein extracted from anyloid deposits induced in mice by injection of either Candida albicans cells or sodium caseinate was found to have chromatographic and electrophoretic properties and an amino-acid compostiion characteristic of the AA class of amyloid proteins. The homology of the mouse protein with 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.73.3.964
更新日期:1976-03-01 00:00:00
abstract::Viral shells are self-assembled protein nanocontainers with remarkable material properties. They combine simplicity of construction with toughness and complex functionality. These properties make them interesting for bionanotechnology. To date we know little about how virus structure determines assembly pathways and s...
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.1105586108
更新日期:2011-08-02 00:00:00
abstract::The GTPase-activating protein (GAP) has been postulated to function either as a negative regulator or as a possible target protein of Ras in mammalian cells and Xenopus oocytes. Ras must be localized in the plasma membrane of vertebrate cells to function, but GAP is localized in the cytosol. To test whether Ras functi...
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.86.17.6630
更新日期:1989-09-01 00:00:00
abstract::An increase in free Ca2+ triggers exocytosis in pituitary nerve terminals leading to an increase in membrane area and membrane capacitance. When Ca2+ is increased by step depolarization, an instantaneous capacitance increase during the first 80 ms is followed by a slow increase extending over several seconds. We measu...
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.91.12.5267
更新日期:1994-06-07 00:00:00
abstract::Mutations are introduced into rearranged Ig variable genes at a frequency of 10(-2) mutations per base pair by an unknown mechanism. Assuming that DNA repair pathways generate or remove mutations, the frequency and pattern of mutation will be different in variable genes from mice defective in repair. Therefore, hyperm...
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.95.12.6953
更新日期:1998-06-09 00:00:00
abstract::An increasing number of protein structures are found to encompass multiple folding nuclei, allowing their structures to be formed by several competing pathways. A typical example is the ribosomal protein S6, which comprises two folding nuclei (sigma1 and sigma2) defining two competing pathways in the folding energy la...
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.0907665106
更新日期:2009-12-22 00:00:00
abstract::Pathogenic Yersinia spp. carry a large common plasmid that encodes a number of essential virulence determinants. Included in these factors are the Yersinia-secreted proteins called Yops. We analyzed the consequences of wild-type and mutant strains of Yersinia pseudotuberculosis interactions with the macrophage cell li...
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.94.19.10385
更新日期:1997-09-16 00:00:00
abstract::Central nervous system (CNS) trauma can result in tissue disruption, neuronal and axonal degeneration, and neurological dysfunction. The limited spontaneous CNS repair in adulthood and aging is often insufficient to overcome disability. Several investigations have demonstrated that targeting HDAC activity can protect ...
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.0907935106
更新日期:2009-11-17 00:00:00
abstract::A fungal colony is a syncytium composed of a branched and interconnected network of cells. Chimerism endows colonies with increased virulence and ability to exploit nutritionally complex substrates. Moreover, chimera formation may be a driver for diversification at the species level by allowing lateral gene transfer b...
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.1220842110
更新日期:2013-08-06 00:00:00
abstract::Respiratory cytochrome c has been found to be phosphorylated at tyrosine 97 in the postischemic brain upon neuroprotective insulin treatment, but how such posttranslational modification affects mitochondrial metabolism is unclear. Here, we report the structural features and functional behavior of a phosphomimetic cyto...
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.1806833115
更新日期:2018-07-31 00:00:00
abstract::Minimally invasive detection of cell death could prove an invaluable resource in many physiologic and pathologic situations. Cell-free circulating DNA (cfDNA) released from dying cells is emerging as a diagnostic tool for monitoring cancer dynamics and graft failure. However, existing methods rely on differences in DN...
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.1519286113
更新日期:2016-03-29 00:00:00
abstract::X-linked hypophosphatemia is the most prevalent inherited form of rickets. In this disorder, rickets results from hyperphosphaturia and inappropriately normal levels of 1,25(OH)2-vitamin D. Current therapy with oral phosphate and vitamin D improves the rickets, but has significant morbidity and does not significantly ...
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.1834060100
更新日期:2003-09-16 00:00:00
abstract::Nicks within one strand of the bacteriophage T5 DNA molecule act as " weak points" for a novel kind mechanical breakage that can be utilized for "dissecting" the genome. The products from sheared T5(+) DNA include five unique double-stranded segments of the molecule and various combinations of adjacent segments. These...
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.71.5.2108
更新日期:1974-05-01 00:00:00
abstract::Besides ethanol, acetic acid is produced in naturally fermenting sweet resources and is a significant environmental stress for fruit-breeding Drosophila populations and species. Although not related to the presence of an active alcohol dehydrogenase, adult acetic acid tolerance was found to correlate with ethanol tole...
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.90.8.3621
更新日期:1993-04-15 00:00:00
abstract::Animal movements result from a complex balance of many different forces. Muscles produce force to move the body; the body has inertial, elastic, and damping properties that may aid or oppose the muscle force; and the environment produces reaction forces back on the body. The actual motion is an emergent property of 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.1011564107
更新日期:2010-11-16 00:00:00
abstract::The C2 domain containing protein extended synaptotagmin (E-Syt) plays important roles in both lipid homeostasis and the intracellular signaling; however, its role in physiology remains largely unknown. Here, we show that hypothalamic E-Syt3 plays a critical role in diet-induced obesity (DIO). E-Syt3 is characteristica...
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.2004392117
更新日期:2020-08-18 00:00:00
abstract::Since the days of Hertz, radio transmitters have evolved from rudimentary circuits emitting around 50 MHz to modern ubiquitous Wi-Fi devices operating at gigahertz radio bands. As wireless data traffic continues to increase, there is a need for new communication technologies capable of high-frequency operation for hig...
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.1903534116
更新日期:2019-05-07 00:00:00
abstract::Prediction of the native tertiary structure of a globular protein from the primary sequence will require a potential energy model that can discriminate all nonnative structures from the native structure(s). A successful model must distinguish not only alternate structures that are very nonnative but also alternate str...
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.92.3.709
更新日期:1995-01-31 00:00:00
abstract::[3H]Puromycin and N-(ethyl-2-diazomalonyl)[3H]puromycin are incorporated into E. coli ribosomes on irradiation at 253.7 nm. Both compounds incorporate into both protein and nucleic acid. Two-dimensional gel electrophoresis of ribosomal protein shows that L23 is the major protein labeled by puromycin. Although incorpor...
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.72.8.2974
更新日期:1975-08-01 00:00:00
abstract::Successful treatment in allergic, autoimmune, and infectious diseases often requires altering the nature of a detrimental immune response mediated by a particular CD4+ T helper (Th) cell subset. While several factors contribute to the development of CD4+ Th1 and Th2 cells, the requirements for switching an established...
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.92.8.3142
更新日期:1995-04-11 00:00:00