Abstract：
:The alpha-helix defined in 1951 by Pauling et al. on the basis of model building and X-ray fibre diffraction data has 3.65 residues per turn (n) achieved with planar peptides, torsion angles of phi = -48 degrees and psi = -57 degrees and hydrogen bonds which are close to linear. Although X-ray analyses of proteins have confirmed the general correctness of the model for the helix, recent high resolution (1.7-1.0 A) diffraction studies have shown that the parameters described by Pauling et al. and later by Perutz and Arnott and Wonacott are not a good description of the alpha-helices in globular proteins, where the mean values of phi, psi are usually close to -63 degrees, -42 degrees. Here we show that these values arise as a mean of two significantly different classes in amphipathic helices depending on whether the peptide carbonyl oxygen is hydrogen bonded to a solvent or polar side-chain atom. The hydrogen bonds made by the hydrophilic carbonyls to the NH groups within helices are longer and less linear than those involving hydrophobic carbonyls. We also show that these effects are associated with a significant curvature of helices in globular proteins. For example, the alpha-helix in avian pancreatic peptide (aPP) has a radius of curvature of approximately 70 A. These results are of significance in the packing of helices in fibrous and globular proteins, in the calculation of their dipole moments, solvent accessibilities and internal energies, and in the theoretical estimation of spectroscopic properties such as circular dichroism and Raman scattering.
journal_name
Naturejournal_title
Natureauthors
Blundell T,Barlow D,Borkakoti N,Thornton Jdoi
10.1038/306281a0subject
Has Abstractpub_date
1983-11-17 00:00:00pages
281-3issue
5940eissn
0028-0836issn
1476-4687journal_volume
306pub_type
杂志文章相关文献
NATURE文献大全abstract：:Anterior-posterior patterning in insects, vertebrates and nematodes involves members of conserved Antennapedia-class homeobox gene clusters (HOM-C) that are thought to give specific body regions their identities. The effects of these genes on region-specific body structures have been described extensively, particularl...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/355255a0
更新日期：1992-01-16 00:00:00
abstract：:Nicotine obtained from tobacco can improve learning and memory on various tasks and has been linked to arousal, attention, rapid information processing, working memory, and long-term memories that can cause craving years after someone has stopped smoking. One likely target for these effects is the hippocampus, a centr...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/383713a0
更新日期：1996-10-24 00:00:00
abstract：:Carbon exchange between the terrestrial biosphere and the atmosphere is one of the key processes that need to be assessed in the context of the Kyoto Protocol. Several studies suggest that the terrestrial biosphere is gaining carbon, but these estimates are obtained primarily by indirect methods, and the factors that ...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/35009084
更新日期：2000-04-20 00:00:00
abstract：:Seafloor spreading is largely unobserved because 98 per cent of the global mid-ocean-ridge system is below the ocean surface. Our understanding of the dynamic processes that control seafloor spreading is thus inferred largely from geophysical observations of spreading events on land at Afar in East Africa and Iceland....
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature20116
更新日期：2016-12-08 00:00:00
abstract：:The actions of many peptide growth factors include both stimulation and inhibition of cell proliferation, as well as effects unrelated to the control of cell growth. One peptide can have both stimulatory and inhibitory activity in a single cell, depending on the context of the other signal molecules present. ...
journal_title：Nature
pub_type： 杂志文章,评审
doi：10.1038/332217a0
更新日期：1988-03-17 00:00:00
abstract：:Prostaglandins have wide-ranging effects in the body and are thought to be important mediators of inflammation. Cyclooxygenase (COX) plays a key regulatory role in prostaglandin synthesis, and occurs in both constitutive (COX-1) and inducible (COX-2) isoforms. COX-1 is thought to provide cytoprotective effects, wherea...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/378406a0
更新日期：1995-11-23 00:00:00
abstract：:Sex is expensive. A population of females that reproduce asexually should prima facie have twice the growth rate of an otherwise equivalent anisogamous sexual population lacking paternal care, or a population with modes of paternal care that can be co-opted by parthenogenetic females. The two leading theories for the ...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/35079578
更新日期：2001-06-07 00:00:00
abstract：:Online hate and extremist narratives have been linked to abhorrent real-world events, including a current surge in hate crimes1-6 and an alarming increase in youth suicides that result from social media vitriol7; inciting mass shootings such as the 2019 attack in Christchurch, stabbings and bombings8-11; recruitment o...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/s41586-019-1494-7
更新日期：2019-09-01 00:00:00
abstract：:The rare Egyptian vulture (Neophron percnopterus) stands out among the Old World vultures (Family Accipitridae) because of its brightly ornamented head, which is coloured yellow by carotenoid pigments, and its practice of feeding on faeces. Here we show that Egyptian vultures obtain these pigments from the excrement o...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/416807a
更新日期：2002-04-25 00:00:00
abstract：:Zooxanthellae, endosymbiotic algae of reef-building corals, substantially contribute to the high gross primary production of coral reefs, but corals exude up to half of the carbon assimilated by their zooxanthellae as mucus. Here we show that released coral mucus efficiently traps organic matter from the water column ...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature02344
更新日期：2004-03-04 00:00:00
abstract：:The cortex organizes sensory information to enable discrimination and generalization1-4. As systematic representations of chemical odour space have not yet been described in the olfactory cortex, it remains unclear how odour relationships are encoded to place chemically distinct but similar odours, such as lemon and o...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/s41586-020-2451-1
更新日期：2020-07-01 00:00:00
abstract：:Knowledge of the composition of the Earth's core is important for understanding its melting point and therefore the temperature at the inner-core boundary and the temperature profile of the core and mantle. In addition, the partitioning of light elements between solid and liquid, as the outer core freezes at the inner...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/35012056
更新日期：2000-05-11 00:00:00
abstract：:In the ocean, the chemical forms of nitrogen that are readily available for biological use (known collectively as 'fixed' nitrogen) fuel the global phytoplankton productivity that exports carbon to the deep ocean. Accordingly, variation in the oceanic fixed nitrogen reservoir has been proposed as a cause of glacial-in...
journal_title：Nature
pub_type： 历史文章,杂志文章
doi：10.1038/nature12397
更新日期：2013-09-12 00:00:00
abstract：:Homopyrimidine oligonucleotides bind to homopurine-homopyrimidine sequences of duplex DNA forming a local triple helix. This binding can be demonstrated either directly by a footprinting technique, gel assays, or indirectly by inducing irreversible reactions in the target sequence, such as photocrosslinking or cleavag...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/344358a0
更新日期：1990-03-22 00:00:00
abstract：:Patchwork homology observed between divergent members of polymorphic multigene families is thought to reflect evolution by short-tract gene conversion (nonreciprocal recombination), although this mechanism cannot usually be confirmed in higher organisms. In contrast to meiotic conversions observed in laboratory yeast ...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/347192a0
更新日期：1990-09-13 00:00:00
abstract：:Curare has long been regarded as a typical competitive antagonist of acetylcholine (ACh) at the vertebrate neuromuscular junction. Recently, however, it has been shown that curare can also block the channels opened by ACh at the frog neuromuscular junction as well as on rat and Aplysia neurones; moreover, curare is ab...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/298272a0
更新日期：1982-07-15 00:00:00
abstract：:The emergence of HIV-1 group M subtype B in North American men who have sex with men was a key turning point in the HIV/AIDS pandemic. Phylogenetic studies have suggested cryptic subtype B circulation in the United States (US) throughout the 1970s and an even older presence in the Caribbean. However, these temporal an...
journal_title：Nature
pub_type： 历史文章,杂志文章
doi：10.1038/nature19827
更新日期：2016-11-03 00:00:00
abstract：:Leukaemia inhibitory factor (LIF) has a variety of effects on different cell types in vitro, inhibiting the differentiation of embryonic stem cells and promoting the survival and/or proliferation of primitive haematopoietic precursors and primordial germ cells. Here we show that LIF-deficient mice derived by gene targ...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/363361a0
更新日期：1993-05-27 00:00:00
abstract：:5-hydroxytryptamine type 3 (5-HT3) receptors are members of the Cys-loop receptor superfamily. Neurotransmitter binding in these proteins triggers the opening (gating) of an ion channel by means of an as-yet-uncharacterized conformational change. Here we show that a specific proline (Pro 8*), located at the apex of th...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature04130
更新日期：2005-11-10 00:00:00
abstract：:The mechanism whereby eukaryotic pre-messenger RNAs are polyadenylated is unknown. Most models for polyadenylation invoke cleavage of precursor transcripts at the site of poly(A) addition followed by polymerization of A residues by poly(A) polymerase. Analysis of the sequences surrounding poly(A) addition sites has id...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/309179a0
更新日期：1984-05-10 00:00:00
abstract：:Calcium (Ca(2+))-activated chloride channels are fundamental mediators in numerous physiological processes including transepithelial secretion, cardiac and neuronal excitation, sensory transduction, smooth muscle contraction and fertilization. Despite their physiological importance, their molecular identity has remain...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature07313
更新日期：2008-10-30 00:00:00
abstract：:Migration of cells in higher organisms is mediated by adhesion receptors, such as integrins, that link the cell to extracellular-matrix ligands, transmitting forces and signals necessary for locomotion. Whether cells will migrate or not on a given substratum, and also their speed, depends on several variables related ...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/385537a0
更新日期：1997-02-06 00:00:00
abstract：:Lymphocyte function-associated antigen-1 (LFA-1) is a heterodimer composed of an alpha and beta chain that is expressed on the surface of most leukocytes and is an essential molecule for adhesion reactions between cells participating in the immune response. A putative ligand for LFA-1 is the intercellular adhesion mol...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/333850a0
更新日期：1988-06-30 00:00:00
abstract：:TATA-binding protein (TBP) binds the minor groove of the TATA element with the DNA bent 80 degrees towards the major groove. A constrained minicircle strategy has been used to test the effect of DNA topology on the affinity of TBP for the TATA element. We report here that TBP bound to DNA which was slightly pre-bent t...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/373724a0
更新日期：1995-02-23 00:00:00
abstract：:Over the past 50 years there has been much speculation about the energetic cost of swimming and wave-riding by dolphins. When aligned properly in front of the bow of moving ships in the stern wake of small boats, on wind waves, and even in the wake of larger cetaceans, the animals appear to move effortlessly through t...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/355821a0
更新日期：1992-02-27 00:00:00
abstract：:We have shown previously that chemically skinned fibre bundles from scallop muscle can be desensitized to the action of calcium by the removal of the regulatory light chains of myosin and that sensitivity can be restored by the re-addition of scallop light chains. We have now confirmed these results and extended our o...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/286626a0
更新日期：1980-08-07 00:00:00
abstract：:The 3-dimethylsulphoniopropionate (DMSP) produced by marine algae is the main biogenic precursor of atmospheric dimethylsulphide (DMS). This biogenic DMS, formed by bacterial and algal degradation of DMSP, contributes about 1.5 x 10(13) g of sulphur to the atmosphere annually, and plays a major part in the global sulp...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/43160
更新日期：1997-06-26 00:00:00
abstract：:Spatial patterning is a ubiquitous feature of biological systems. Meiotic crossovers provide an interesting example, defined by the classic phenomenon of crossover interference. Here we identify a molecular pathway for interference by analysing crossover patterns in budding yeast. Topoisomerase II plays a central role...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature13442
更新日期：2014-07-31 00:00:00
abstract：:When simian virus 40 (SV40) infects host cells, the viral genes are expressed in two phases. Early in infection, the virus genome is transcribed and translated to yield two related proteins, 'large T' and 'small t' antigens. Later the rate of synthesis of the early messenger RNA falls and the viral genes coding for th...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/289810a0
更新日期：1981-02-26 00:00:00
abstract：:The mobilization of aluminium from acidic forest soils is arguably the most ecologically important consequence of acid deposition in the environment because of its adverse effects on soils, forest vegetation and surface water. Here we show that there has been a significant decline in the concentrations of aluminium sp...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/417242a
更新日期：2002-05-16 00:00:00
