Abstract:
:The local conformations of proteins and peptides are determined by the amino acid sequence. However, the 20 amino acids encoded by the genome allow the peptide backbone to fold into many conformations, so that even for a small peptide it becomes very difficult to predict the three-dimensional structure. By using empirical conformational energy calculations, a set of amino acids has been designed that would be expected to constrain the conformation of a peptide or a protein to one or two local minima. Most of these amino acids are based on asymmetric substitutions at the C alpha atom of each residue. The H alpha atom of alanine was replaced by various groups: -OCH3, -NCH3, -SCH3, -CONH2, -CONHCH3, -CON(CH3)2, -NH.CO.CH3, -phenyl, or -o-(OCH3)phenyl. Several of these new amino acids are predicted to fold into unique peptide conformations such as right-handed alpha-helical, left-handed alpha-helical, or extended. In an attempt to produce an amino acid that favored the C(eq)7 conformation (torsion angles: phi = -70 degrees and psi = +70 degrees), an extra amide group was added to the C beta atom of the asparagine side chain. Conformationally restricted amino acids of this type could prove useful for developing new peptide pharmaceuticals, catalysts, or polymers.
journal_name
Proc Natl Acad Sci U S Aauthors
Burgess AWdoi
10.1073/pnas.91.7.2649subject
Has Abstractpub_date
1994-03-29 00:00:00pages
2649-53issue
7eissn
0027-8424issn
1091-6490journal_volume
91pub_type
杂志文章abstract::Infectious RNA transcripts were generated from full-length cDNA clones of the tobacco etch potyvirus genome containing an insertion of the bacterial beta-glucuronidase (GUS) gene between the polyprotein-coding sequences for the N-terminal 35-kDa proteinase and the helper component-proteinase. The recombinant virus was...
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.89.21.10208
更新日期:1992-11-01 00:00:00
abstract::Originally recognized for their role in lipoprotein metabolism and cardiovascular disease, apolipoprotein (apo) E isoforms (apoE2, apoE3, and apoE4) have also been implicated to play a key role in several biological processes not directly related to their lipid transport function. For example, apoE4 contributes signif...
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.0803526105
更新日期:2008-06-24 00:00:00
abstract::The objective of this study has been to determine which Na,K-ATPase isoforms are expressed in red blood cells and whether kinetic differences in the uncoupled sodium efflux mode between the human red blood cell Na,K-ATPase and other preparations can be explained by differences in the underlying subunit composition. To...
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.94.11.5943
更新日期:1997-05-27 00:00:00
abstract::We present a model describing how Mg(2+) binds and stabilizes specific RNA structures. In this model, RNA stabilization arises from two energetically distinct modes of Mg(2+) binding: diffuse- and site-binding. Diffusely bound Mg(2+) are electrostatically attracted to the strong anionic field around the RNA and are ac...
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.221234598
更新日期:2001-10-23 00:00:00
abstract::Synaptic loss is the cardinal feature linking neuropathology to cognitive decline in Alzheimer's disease (AD). However, the mechanism of synaptic damage remains incompletely understood. Here, using FRET-based glutamate sensor imaging, we show that amyloid-β peptide (Aβ) engages α7 nicotinic acetylcholine receptors to ...
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.1306832110
更新日期:2013-07-02 00:00:00
abstract::Many important hominid-bearing fossil localities in East Africa are in regions that are extremely hot and dry. Although humans are well adapted to such conditions, it has been inferred that East African environments were cooler or more wooded during the Pliocene and Pleistocene when this region was a central stage 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.1001824107
更新日期:2010-06-22 00:00:00
abstract::Surgical removal of one or both atrial appendages was employed in rats to reduce the intrinsic stores of atriopeptin (AP). In conscious rats (with intact baroreceptor reflexes), bilateral or unilateral atrial appendectomy suppressed the diuresis and natriuresis produced by acute volume expansion. Surprisingly, volume ...
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.85.9.3155
更新日期:1988-05-01 00:00:00
abstract::Excessive activation of poly(ADP-ribose) polymerase 1 (PARP1) leads to NAD(+) depletion and cell death during ischemia and other conditions that generate extensive DNA damage. When activated by DNA strand breaks, PARP1 uses NAD(+) as substrate to form ADP-ribose polymers on specific acceptor proteins. These polymers 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.211202598
更新日期:2001-10-09 00:00:00
abstract::J-domain chaperones are involved in the efficient handover of misfolded/partially folded proteins to Hsp70 but also function independently to protect against cell death. Due to their high flexibility, the mechanism by which they regulate the Hsp70 cycle and how specific substrate recognition is performed remains unkno...
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.1914999116
更新日期:2019-10-22 00:00:00
abstract::Understanding the causes and consequences of wildfires in forests of the western United States requires integrated information about fire, climate changes, and human activity on multiple temporal scales. We use sedimentary charcoal accumulation rates to construct long-term variations in fire during the past 3,000 y in...
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.1112839109
更新日期:2012-02-28 00:00:00
abstract::The unique specificity of monoclonal antibodies (Ab) was combined with the cell-killing function of the cytolytic alternative pathway of complement. The functionally C3b-like glycoprotein of cobra venom was linked to a murine monoclonal Ab directed to a human melanoma-associated antigen by a disulfide bond, by using 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.78.12.7707
更新日期:1981-12-01 00:00:00
abstract::Theories of density-dependent natural selection predict that evolution should favor those genotypes with the highest per capita rates of population growth under the current density conditions. These theories are silent about the mechanisms that may give rise to these increases in density-dependent growth rates. We hav...
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.88.23.10905
更新日期:1991-12-01 00:00:00
abstract::The structure of the gene encoding human hexabrachion (tenascin) has been determined from overlapping clones isolated from a human genomic bacteriophage library. The genomic inserts were characterized by restriction mapping, Southern blot analysis, PCR, and DNA sequencing. The coding region of the hexabrachion gene sp...
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.88.21.9438
更新日期:1991-11-01 00:00:00
abstract::When either the homologous RNA (avian myeloblastosis virus RNA) or a heterologous RNA (poliovirus RNA) was used as a template, the anticomplementary DNA synthesized in vitro by avian myeloblastosis virus reverse transcriptase (RNA-directed DNA nucleotidyltransferase, EC 2.7.7.7) was primed by fragments of the original...
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.77.3.1316
更新日期:1980-03-01 00:00:00
abstract::Palmitoylation is a common lipid modification known to regulate the functional properties of various proteins and is a vital step in the biosynthesis of voltage-activated sodium (Nav) channels. We discovered a mutation in an intracellular loop of rNav1.2a (G1079C), which results in a higher apparent affinity for exter...
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.1108497108
更新日期:2011-12-13 00:00:00
abstract::The SecY protein of Escherichia coli is an integral membrane component of the protein export apparatus. Suppressor mutations in the secY gene (prlA alleles) have been isolated that restore the secretion of precursor proteins with defective signal sequences. These mutations have never been shown to affect the transloca...
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.93.12.5953
更新日期:1996-06-11 00:00:00
abstract::Androgen receptor (AR) protein expression and function are critical for survival and proliferation of androgen-sensitive (AS) prostate cancer cells. Besides its ability to function as a transcription factor, experimental observations suggest that AR becomes a licensing factor for DNA replication in AS prostate cancer ...
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.0603057103
更新日期:2006-10-10 00:00:00
abstract::The atomic buckling in 2D "Xenes" (such as silicene) fosters a plethora of exotic electronic properties such as a quantum spin Hall effect and could be engineered by external strain. Quantifying the buckling magnitude with subangstrom precision is, however, challenging, since epitaxially grown 2D layers exhibit comple...
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.1913489117
更新日期:2020-01-07 00:00:00
abstract::As a first step in assessing the efficacy of a gene transfer approach to the induction of transplantation tolerance in our miniature swine model, double-copy retroviral vectors engineered to express a drug-resistance marker (neomycin) and a swine class II DRB cDNA were constructed. Infectious particles containing thes...
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.88.21.9760
更新日期:1991-11-01 00:00:00
abstract::The photosynthetic apparatus converts light into chemical energy by a series of reactions that give rise to a coupled flow of electrons and protons that generate reducing power and ATP, respectively. A key intermediate in these reactions is plastoquinone (PQ), the most abundant electron and proton (hydrogen) carrier 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.84.23.8424
更新日期:1987-12-01 00:00:00
abstract::Polycomb group proteins are essential regulators of developmental processes across animals. Despite their importance, studies on Polycomb are often restricted to classical model systems and, as such, little is known about the evolution of these important chromatin regulators. Here we focus on Polycomb Repressive Compl...
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.2005136117
更新日期:2020-09-15 00:00:00
abstract::Secreted parasitism proteins encoded by parasitism genes expressed in esophageal gland cells mediate infection and parasitism of plants by root-knot nematodes (RKN). Parasitism gene 16D10 encodes a conserved RKN secretory peptide that stimulates root growth and functions as a ligand for a putative plant transcription ...
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.0604698103
更新日期:2006-09-26 00:00:00
abstract::Ionizing radiation has been used to selectively separate the circadian oscillator function of the eye of Aplysia from some of its other functions--synchronous compound action potential (CAP) generation, the light response, synaptic transmission between photoreceptors and output neurons, and the bursting pacemaker mech...
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.77.9.5542
更新日期:1980-09-01 00:00:00
abstract::The role of various adhesion molecules in lymphocyte homing to the brain and in inflammatory autoimmune disease of the central nervous system (CNS) was examined in mice. Activated T cell lines and clones expressed CD44 and integrin alpha4, but not L-selectin, and entered the CNS independent of their antigen specificit...
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.96.12.6896
更新日期:1999-06-08 00:00:00
abstract::Tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) plays a vital role in immune signal transduction pathways by acting as a ubiquitin ligase (E3) for Lys63-linked polyubiquitin chain synthesis. However, the detailed mechanism by which the TRAF6 RING dimer promotes ubiquitin transfer was unknown. Through ...
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.1721788115
更新日期:2018-02-20 00:00:00
abstract::Type 2 diabetes mellitus (T2DM) is strongly associated with obesity in most, but not all, ethnic groups, suggesting important ethnic differences in disease susceptibility. Although it is clear that insulin resistance plays a major role in the pathogenesis of T2DM and that insulin resistance is strongly associated with...
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.0608537103
更新日期:2006-11-28 00:00:00
abstract::Lewy bodies and Lewy neurites are the defining neuropathological characteristics of Parkinson's disease and dementia with Lewy bodies. They are made of abnormal filamentous assemblies of unknown composition. We show here that Lewy bodies and Lewy neurites from Parkinson's disease and dementia with Lewy bodies are stai...
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.95.11.6469
更新日期:1998-05-26 00:00:00
abstract::A discussion of the range of applicability of Forster long-range energy transfer in the determination of macromolecular dimensions and conformational dynamics is given. Emphasis is laid on the effect of restrictions in the orientational freedom of donor and acceptor and on the importance of the orientational averaging...
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.73.2.271
更新日期:1976-02-01 00:00:00
abstract::We have used (13C)-1H NMR spectroscopy at 360.13 MHz to resolve the 13C coupled proton resonance of glutamate and lactate in the rat brain in vivo. The time required for the 13C fractional enrichment of the 4-CH2 position of brain glutamate to reach isotopic steady state was determined during a continuous infusion 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.82.6.1633
更新日期:1985-03-01 00:00:00
abstract::Mechanism of enzymatic conversion of a fatty acid to the corresponding alkane by the loss of the carboxyl carbon was investigated with particulate preparations from Pisum sativum. A heavy particulate preparation (sp. gr., 1.30 g/cm3) isolated by two density-gradient centrifugation steps catalyzed conversion of octadec...
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.81.21.6613
更新日期:1984-11-01 00:00:00