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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Immunoisolation techniques have led to the purification of apical and basolateral transport vesicles that mediate the delivery of proteins from the trans-Golgi network to the two plasma membrane domains of MDCK cells. We showed previously that these transport vesicles can be formed and released in the presence of ATP from mechanically perforated cells (Bennett, M. K., A. Wandinger-Ness, and K. Simons, 1988. EMBO (Euro. Mol. Biol. Organ.) J. 7:4075-4085). Using virally infected cells, we have monitored the purification of the trans-Golgi derived vesicles by following influenza hemagglutinin or vesicular stomatitis virus (VSV) G protein as apical and basolateral markers, respectively. Equilibrium density gradient centrifugation revealed that hemagglutinin containing vesicles had a slightly lower density than those containing VSV-G protein, indicating that the two fractions were distinct. Antibodies directed against the cytoplasmically exposed domains of the viral spike glycoproteins permitted the resolution of apical and basolateral vesicle fractions. The immunoisolated vesicles contained a subset of the proteins present in the starting fraction. Many of the proteins were sialylated as expected for proteins existing the trans-Golgi network. The two populations of vesicles contained a number of proteins in common, as well as components which were enriched up to 38-fold in one fraction relative to the other. Among the unique components, a number of transmembrane proteins could be identified using Triton X-114 phase partitioning. This work provides evidence that two distinct classes of vesicles are responsible for apical and basolateral protein delivery. Common protein components are suggested to be involved in vesicle budding and fusion steps, while unique components may be required for specific recognition events such as those involved in protein sorting and vesicle targeting.
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PMID:Distinct transport vesicles mediate the delivery of plasma membrane proteins to the apical and basolateral domains of MDCK cells. 220 40

Preliminary crystallographic data are given for two molecules involved in the interaction between the humoral immune response and the influenza virus. These molecules are the Fab fragment of an antibody specific for the haemagglutinin of influenza virus strain X31 (Hong Kong 1/68 (H3N2)) and a mutant of X31 haemagglutinin that escapes recognition by that antibody. Crystals of the haemagglutinin are isomorphous to those of X31, whose structure is known; they diffract to 3.4 A resolution. Crystals of the Fab fragment are trigonal with space group P3(1)21 (or P3(2)21) and diffract to 2.6 A resolution. The unit cell dimensions are a = b = 98.9 A, c = 89.2 A. A native data set has been collected for both proteins.
J Mol Biol 1990 Dec 05
PMID:Crystallization and preliminary X-ray diffraction studies of a monoclonal antibody Fab fragment specific for an influenza virus haemagglutinin and of an escape mutant of that haemagglutinin. 225 27

A new approach to create chimeric genes by directed exchange of oligonucleotide fragments was developed. By oligonucleotide-directed mutagenesis a few deletion mutants of the influenza virus hemagglutinin (HA) gene were obtained. These variants of HA gene contain unique restriction sites in DNA regions coding for the A and B epitopes of the HA molecule. The obtained special vectors may be used for cloning DNA fragments coding for new amino acid sequences in internal sites of the HA gene.
Mol Biol (Mosk)
PMID:[Directed reconstruction of the influenza virus hemagglutinin gene]. 229 Apr 20

Cadherins are a family of integral membrane glycoproteins that mediate homophilic, calcium-dependent cell adhesion in vertebrate species. The primary structures of six members of the cadherin family have recently been determined. The extracellular portion of these proteins is composed of five domains, the first of which is the most highly conserved among cadherins. Previous searches of protein sequence databases have revealed little or no sequence homology between cadherins and other proteins. Here we report that the first extracellular domain of cadherins exhibits substantial sequence homology with the amino termini of influenza strain A hemagglutinins. These regions of sequence homology have been shown to be functionally important in both cadherins and hemagglutinins. Our observations suggest that a functional domain of cadherins is conserved among other proteins.
J Mol Biol 1990 Feb 20
PMID:Identification of a conserved region common to cadherins and influenza strain A hemagglutinins. 231 92

We have applied the method of simulated annealing to the refinement of the 3 A resolution crystal structure of the influenza virus hemagglutinin glycoprotein, using the program X-PLOR. Two different methods were introduced into X-PLOR to treat the non-crystallographic symmetry present in this and in other crystal structures. In the first, only the unique protomer atoms are refined; by application of the non-crystallographic symmetry operators to the protomer atoms, the X-ray structure factor derivatives are effectively averaged, and a non-bonded energy term models the interactions of the protomer with its neighbors in the oligomer without explicit refinement of the other protomers in the crystallographic asymmetric unit. In the second method, the entire asymmetric unit is refined, but an effective energy term is added to the empirical energy that restrains symmetry-related atomic positions to their average values after least-squares superposition. Several other modifications and additions were made to previously published X-PLOR protocols, including weighting of the X-ray terms, maintenance of the temperature of the molecular dynamics simulation, treatment of charged groups, changes in the values of certain empirical energy parameters, and the use of N-linked carbohydrate empirical energy parameters. The hemagglutinin refinement proceeded in several stages. An initial round of simulated annealing of the monomer was followed by rigid-body refinement of the 3-fold non-crystallographic symmetry axis position and a second round of monomer refinement. A third round was performed on the trimer using non-crystallographic symmetry restraints in all regions except those in lattice contacts showing obvious derivations from 3-fold symmetry. The refinement was completed with several rounds of conventional positional and isotropic temperature factor refinement needed to correct bad model geometry introduced by high-temperature molecular dynamics in regions of weak electron density. This structure was then used as the basis for refinement of three crystallographically isomorphous hemagglutinin structures, including complexes with the influenza virus receptor, sialic acid. Model geometry comparable to well-refined high-resolution structures was obtained with relatively little manual intervention, demonstrating the ability of simulated annealing refinement to produce highly idealized structures at moderate resolution.
J Mol Biol 1990 Apr 20
PMID:Refinement of the influenza virus hemagglutinin by simulated annealing. 232 80

Deproteinization effect of nonionic detergent NP-40 on orthomyxoviruses and paramyxoviruses depends on the ionic strength and pH of the medium. Solubilization of the M1 protein is considerably more efficient at pH 6.0-5.0 than at pH 6.5-9.0 for influenza types A, B, C viruses. In contrast, the extraction of matrix protein M from the virions of paramyxoviruses is increased at pH about 9.0. The phenomenon of pH-dependent solubilization of the virions matrix protein is analyzed in connection with the mechanisms of viral invasion of the target cell. Polypeptide M1 is found to be more tightly bound with the nucleocapside of influenza virus with the cleaved hemagglutinine HA1/2 than with the nucleocapside of the virus with the intact HA0.
Mol Gen Mikrobiol Virusol 1990 Mar
PMID:[The effect of pH on in vitro deproteinization in orthomyxo- and paramyxoviruses]. 236 97

New crystalline forms of tetrameric neuraminidase heads from two strains (B/Lee/40 and B/mem/89) of type B human influenza virus were obtained and the crystals diffracted using X-rays to 2.5 A resolution without lattice disorder. The new B/Lee/40 crystalline form is tetragonal, space group P42(1)2, with unit cell dimensions a = 123.8 A, c = 71.8 A. The B/mem/89 crystalline form is also tetragonal, space group I422, with unit cell dimensions a = 122.9 A, c = 164.4 A. There is one neuraminidase monomer per asymmetric unit in both forms.
J Mol Biol 1990 Aug 05
PMID:New crystalline forms of neuraminidase of type B human influenza virus. 238 63

The nature of amino acid replacements in 16 drift variants of hemagglutinin H3 subtype and 5 drift variants of neuraminidase N2 subtype of the influenza A virus were studied. The dependences of relative replacement frequencies and relative quantities of frequent replacements upon differences of properties of substituted residues are plotted. In contrast to most of the known proteins, amino acid replacements in hemagglutinin and neuraminidase depend weakly on the physico-chemical parameters of amino acids. For the antigenic determinants studied the replacement frequencies were compared to those calculated according to two models: one for conservative replacements and the other for accidental mutation of the genetic code. The differences in the nature of amino acid replacements are found in four antigenic determinants of hemagglutinin. The replacements in experimentally selected proteins are shown to go beyond limitations of natural variants. The explanations of the reasons of low epidemicity of some strains and ineffective attempt to imitate the natural antigenic drift of viruses by using experimental selection are proposed. The causes of time-limited circulation of H3N2 influenza virus subtype are discussed.
Mol Biol (Mosk)
PMID:[The nature of amino acid substitution in antigenic drift of hemagglutinin N3 and neuraminidase N2 from the influenza virus]. 242 40

The data from literature and authors own studies are reviewed on variability of human influenza viral strains, isolated during the same epidemic season in different periods of pandemic cycle. The data obtained indicate that variability of epidemic strains of human influenza virus deals with the genes coding for outer membrane proteins (hemagglutinin and neuraminidase) as well as nonglycosylated proteins. Circulation of a number of viral variants of the same serotype, differing in antigenic specificity of outer membrane proteins or in the genes coding for nonglycosylated proteins was registered during one and the same season of one epidemic. During circulation of viral variants of the same serotype recombination may take place. Heterogeneity of viral strains circulating during different epidemic seasons of the same pandemic cycle is different. The possible mechanisms of development of the new epidemic variants of human influenza virus are discussed.
Mol Gen Mikrobiol Virusol 1985 Aug
PMID:[Molecular basis of the variability of epidemic strains of human influenza viruses]. 243 23

The crossreacting glycosylated host component (COHC) of influenza virus propagated in chick embryo has been studied using the monoclonal antibodies (MA). The specificity of MA to COHC has been demonstrated by different methods. Both MA of clones A9 and B7 react with the spatially overlapping antigenic sites of oligosaccharide chain, but only MA of B7 are active in hemagglutination inhibition test. The COHC is shown to be associated with both surface glycoprotein adsorbing on the surface of the virion. The study of the components from the allantonic fluid has shown the COHC to be associated with the sole embryo glycoprotein with the mol. mass around 150 kD and p1 9.0-9.5. Thus, the glycoprotein is possibly identical with the glycoprotein adsorbing on the virion surface. The content of COHC in various preparations of influenza virions has been also studied. The relative content of COHC is shown to increase during the purification of viral preparation. The COHC effect on the characteristics of vaccine preparations is discussed.
Mol Gen Mikrobiol Virusol 1987 Feb
PMID:[Study of the host glycosyl component of the influenza virus using monoclonal antibodies]. 243 46


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