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排序方式: 共有220条查询结果,搜索用时 15 毫秒
1.
Structural relatedness of lysis proteins from colicinogenic plasmids and icosahedral coliphages 总被引:4,自引:0,他引:4
The host-lysis-inducing functions of phi X174 protein E and MS2 protein L
were recently shown to reside on the N-terminal and C-terminal halves of
the two respective lysis proteins. In the present study it is shown that
the small lysis proteins encoded in various colicinogenic plasmids share
local sequence similarities and certain structural characteristics with the
essential peptides of their coliphage-coded counterparts. Despite their
dissimilar sizes and origins, it is suggested that the colicinogenic lysis
proteins are functionally analogous and evolutionarily related to those of
icosahedral single- stranded DNA and RNA phages.
相似文献
2.
Cecilia PC Soh Alastair SR Donald James Feeney Walter TJ Morgan Winifred M Watkins 《Glycoconjugate journal》1989,6(3):319-332
The tetrasaccharides GalNAcß1-4[NeuAc2-3]Galß1-4Glc and GalNAcß1-4[NeuAc2-3]Galß1-4GlcNAc were synthesised by enzymic transfer of GalNAc from UDP-GalNAc to 3-sialyllactose (NeuAc2-3Galß1-4Glc) and 3-sialyl-N-acetyllactosamine (NeuAc2-3Galß1-4GlcNAc). The structures of the products were established by methylation and1H-500 MHz NMR spectroscopy. In Sda serological tests the product formed with 3-sialyl-N-acetyllactosamine was highly active whereas that formed with 3-sialyllactose had only weak activity. 相似文献
3.
Phillip A Patten Russell J Howard Willem PC Stemmer 《Current opinion in biotechnology》1997,8(6):724-733
DNA shuffling is a practical process for directed molecular evolution which uses recombination to dramatically accelerate the rate at which one can evolve genes. Single and multigene traits that require many mutations for improved phenotypes can be evolved rapidly. DNA shuffling technology has been significantly enhanced in the past year, extending its range of applications to small molecule pharmaceuticals, pharmaceutical proteins, gene therapy vehicles and transgenes, vaccines and evolved viruses for vaccines, and laboratory animal models. 相似文献
4.
Linkage studies in familial Alzheimer disease: Evidence for chromosome 19 linkage 总被引:41,自引:14,他引:27
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M. A. Pericak-Vance J. L. Bebout P. C. Gaskell L. H. Yamaoka W.-Y. Hung M. J. Alberts A. P. Walker R. J. Bartlett C. A. Haynes K. A. Welsh N. L. Earl A. Heyman C. M. Clark A. D. Roses 《American journal of human genetics》1991,48(6):1034-1050
A genetic component in the etiology of Alzheimer disease (AD) has been supported by indirect evidence for several years, with autosomal dominant inheritance with age-dependent penetrance being suggested to explain the familial aggregation of affecteds. St. George Hyslop et al. reported linkage of familial AD (FAD) in four early-onset families (mean age at onset [M] less than 50 years). Subsequent studies have been inconsistent in their results; Goate et al. also reported positive lod scores. However, both Pericak-Vance et al.'s study of a series of mainly late-onset FAD families (M greater than 60 years) and Schellenberg et al.'s study failed to confirm linkage to chromosome 21 (CH21). These various studies suggest the possibility of genetic heterogeneity, with some families linked to CH21 and others unlocalized. Recently, St. George Hyslop et al. extended their analysis to include additional families. The extended analyses supported their earlier finding of linkage to CH21, while showing strong evidence of heterogeneity between early-onset (M less than 65 years) and late-onset (M greater than 60 years) FAD families. Because our families did not show linkage to CH21, we undertook a genomic search for an additional locus for FAD. Because of both the confounding factor of late age at onset of FAD and the lack of clear evidence of Mendelian transmission in some of our families, we employed the affected-pedigree-member (APM) method of linkage analysis as an initial screen for possible linkage. Using this method, we identified two regions suggesting linkage: the proximal long arm of chromosome 19 (CH19) and the CH21 region of FAD linkage reported by St. George Hyslop et al. Application of standard likelihood (LOD score) analysis to these data support the possibility of an FAD gene locate on CH19, particularly in the late-onset FAD families. These data further suggest genetic heterogeneity and delineate this region of CH19 as an area needing additional investigation in FAD. 相似文献
5.
Folkvord Frans Veltri Giuseppe A. Lupiáñez-Villanueva Francisco Tornese Pietro Codagnone Cristiano Gaskell George 《The International Journal of Life Cycle Assessment》2020,25(5):883-899
The International Journal of Life Cycle Assessment - Given the increasing importance of political decision-making to reduce emission targets, the main purpose of the current paper is to identify... 相似文献
6.
Eva Veronesi Frank Antony Simon Gubbins Nick Golding Alison Blackwell Peter PC. Mertens Joe Brownlie Karin E. Darpel Philip S. Mellor Simon Carpenter 《PloS one》2013,8(8)
Background
Culicoides biting midges (Diptera: Ceratopogonidae) are the biological vectors of globally significant arboviruses of livestock including bluetongue virus (BTV), African horse sickness virus (AHSV) and the recently emerging Schmallenberg virus (SBV). From 2006–2009 outbreaks of BTV in northern Europe inflicted major disruption and economic losses to farmers and several attempts were made to implicate Palaearctic Culicoides species as vectors. Results from these studies were difficult to interpret as they used semi-quantitative RT-PCR (sqPCR) assays as the major diagnostic tool, a technique that had not been validated for use in this role. In this study we validate the use of these assays by carrying out time-series detection of BTV RNA in two colony species of Culicoides and compare the results with the more traditional isolation of infectious BTV on cell culture.Methodology/Principal Findings
A BTV serotype 1 strain mixed with horse blood was fed to several hundred individuals of Culicoides sonorensis (Wirth & Jones) and C. nubeculosus (Mg.) using a membrane-based assay and replete individuals were then incubated at 25°C. At daily intervals 25 Culicoides of each species were removed from incubation, homogenised and BTV quantified in each individual using sqPCR (Cq values) and virus isolation on a KC-C. sonorensis embryonic cell line, followed by antigen enzyme-linked immunosorbent assay (ELISA). In addition, comparisons were also drawn between the results obtained with whole C. sonorensis and with individually dissected individuals to determine the level of BTV dissemination.Conclusions/Significance
Cq values generated from time-series infection experiments in both C. sonorensis and C. nubeculosus confirmed previous studies that relied upon the isolation and detection of infectious BTV. Implications on the testing of field-collected Culicoides as potential virus vectors by PCR assays and the use of such assays as front-line tools for use in diagnostic laboratories in this role are discussed. 相似文献7.
8.
Protein targeting of an unusual, evolutionarily conserved adenylate kinase to a eukaryotic flagellum
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The eukaryotic flagellum is a large structure into which specific constituent proteins must be targeted, transported and assembled after their synthesis in the cytoplasm. Using Trypanosoma brucei and a proteomic approach, we have identified and characterized a novel set of adenylate kinase proteins that are localized to the flagellum. These proteins represent unique isoforms that are targeted to the flagellum by an N-terminal extension to the protein and are incorporated into an extraaxonemal structure (the paraflagellar rod). We show that the N-terminal extension is both necessary for isoform location in the flagellum and sufficient for targeting of a green fluorescent protein reporter protein to the flagellum. Moreover, these N-terminal extension sequences are conserved in evolution and we find that they allow the identification of novel adenylate kinases in the genomes of humans and worms. Given the existence of specific isoforms of certain central metabolic enzymes, and targeting sequences for these isoforms, we suggest that these isoforms form part of a complex, "solid-phase" metabolic capability that is built into the eukaryotic flagellum. 相似文献
9.
A kinesin heavy chain (KIF5A) mutation in hereditary spastic paraplegia (SPG10) 总被引:17,自引:0,他引:17
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Reid E Kloos M Ashley-Koch A Hughes L Bevan S Svenson IK Graham FL Gaskell PC Dearlove A Pericak-Vance MA Rubinsztein DC Marchuk DA 《American journal of human genetics》2002,71(5):1189-1194
We have identified a missense mutation in the motor domain of the neuronal kinesin heavy chain gene KIF5A, in a family with hereditary spastic paraplegia. The mutation occurs in the family in which the SPG10 locus was originally identified, at an invariant asparagine residue that, when mutated in orthologous kinesin heavy chain motor proteins, prevents stimulation of the motor ATPase by microtubule-binding. Mutation of kinesin orthologues in various species leads to phenotypes resembling hereditary spastic paraplegia. The conventional kinesin motor powers intracellular movement of membranous organelles and other macromolecular cargo from the neuronal cell body to the distal tip of the axon. This finding suggests that the underlying pathology of SPG10 and possibly of other forms of hereditary spastic paraplegia may involve perturbation of neuronal anterograde (or retrograde) axoplasmic flow, leading to axonal degeneration, especially in the longest axons of the central nervous system. 相似文献
10.
Salehi Z Geffers L Vilela C Birkenhäger R Ptushkina M Berthelot K Ferro M Gaskell S Hagan I Stapley B McCarthy JE 《Molecular microbiology》2002,46(1):49-62
A number of eukaryotic proteins are already known to orchestrate key steps of mRNA metabolism and translation via interactions with the 5' m7GpppN cap. We have characterized a new type of histidine triad (HIT) motif protein (Nhm1) that co-purifies with the cap-binding complex eIF4F of Schizosaccharomyces pombe. Nhm1 is an RNA-binding protein that binds to m7GTP-Sepharose, albeit with lower specificity and affinity for methylated GTP than is typical for the cap-binding protein known as eukaryotic initiation factor 4E. Sequence searches have revealed that proteins with strong sequence similarity over all regions of the new protein exist in a wide range of eukaryotes, yet none has been characterized up to now. However, other proteins that share specific motifs with Nhm1 include the human Fhit tumour suppressor protein and the diadenosine 5', 5"'-P1, P4-tetraphosphate asymmetrical hydrolase of S. pombe. Our experimental work also reveals that Nhm1 inhibits translation in a cell-free extract prepared from S. pombe, and that it is therefore a putative translational modulator. On the other hand, purified Nhm1 manifests mRNA decapping activity, yet is physically distinct from the Saccharomyces cerevisiae decapping enzyme Dcp1. Moreover, fluorescence and immunofluorescence microscopy show that Nhm1 is predominantly, although not exclusively, nuclear. We conclude that Nhm1 has evolved as a special branch of the HIT motif superfamily that has the potential to influence both the metabolism and the translation of mRNA, and that its presence in S. pombe suggests the utilization of a novel decapping pathway. 相似文献