scholarly journals Algorithm for detection of algebraic Bayesian network primary structure acyclicity based on its quaternary structure

2014 ◽  
Vol 4 (19) ◽  
pp. 128
Author(s):  
Andrey Alexandrovich Filchenkov ◽  
Alexander Lvovich Tulupyev
Keyword(s):  
Bayesian Network ◽  
Primary Structure ◽  
Quaternary Structure

scholarly journals The Prion

2005 ◽  
Vol 43 (1) ◽  
Author(s):  
Paul Gibbons
Keyword(s):  
Immune Response ◽  
Primary Structure ◽  
Nervous Tissue ◽  
Quaternary Structure ◽  
Clinical Symptoms ◽  
Cranial Nerves ◽  
Tnf Alpha ◽  
Mutant Form ◽  
Natural Immunity ◽  
Symptômes Cliniques

Transmissible spongifonn encephalopathies (TSE) have been documented in livestock  for centuries but the nature of the putative causative agent as a contagious, mutant form of a host-encoded protein is a very recent discovery whose nuances remain  unclear. In its normal conformation, the Prion is believed to be a short-lived uptake protein ubiquitous in nervous tissues.In contrast ,the mutant Prion usually has an identical primary structure , but has a radically different tertiary and quaternary structure that confers on it unusual stability and resistance  to the  normal post-translational reactions. Most importantly,  the mutant protein binds to the normal Prion protein and alters its conformation to the mutant form. Transmission of TSE from host to host  has been observed to occur primarily through ingestion of infected tissue and introduction of the mutant Prion to nervous tissue in the mouth, such as the cranial nerves serving the tongue. It is believed that the mutant Prion is transported within the parenchyma via highly motile microglia. The latent damage from eventual accumulation of mutant Prion is the result of the host's immune response to the protein that involves inflammatory TNF-alpha and IL-1 alpha and beta, among others. Clinical symptoms, however , presented well after the host's immune response resulted in spongiform changes to nervous tissue. Fortunately, there currently exists promising research that seeking to explain natural immunity to TSE and apply it to unaffected individuals.Les encaphalopathies spongiformes transmissibles (EST) sont signalees chez le betail depuis des siecles, mais la nature de l'agent causal presume, une forme mutante contagieuse de proteine encodee par l'hote, est une decouverte tres recente qui reste mysterieuse sous bien des rapports. Dans sa conformation normale, le prion serait une proteine messagere dont la vie est courte et qui serait tres repandue dans les tissus nerveux. Par centre, si le prion mutant a une structure primaire identique, sa structure tertiaire et sa structure quatemaire sont completement differentes et lui conferent une stabilite et une resistance inhabituelles aux reactions post-traductionnelles normales . Et cequi est plus important, la proteine prion mutante se lie a la proteine normale et modifie sa conformation pour la transformer en proteine mutante. On a observe que la transmission des EST d'un h6te a l'autre s'effectue principalement par l'ingestion de tissus infectes et l'introduction du prion mutant dans les tissus nerveux par voie orale, notamment par les nerfs craniens au niveau de la langue. On croit que le prion est transporte dans le parenchyme par des microglies tres mobiles. Les dommages latents d'une accumulation eventuelle du prion resultent de la reaction immunitaire de l'hote envers la proteine qui fait intervenir le TNF-alpha et les IL-1 alpha et beta, entre autres . Les symptomes cliniques, toutefois , qui se presentent longtemps apres la reaction immunitaire de l'hote, consistent en des modifications spongiformes au niveau des tissus nerveux. Heureusement, des recherches prometteuses tentent d'expliquer l'immunite naturelle envers les EST et de l'appliquer aux sujets non atteints.

scholarly journals Retrotranslocation: Endoplasmic Reticulum’s Junk Disposal Mechanism

2016 ◽  
Vol 21 (1) ◽  
pp. 9
Author(s):  
Partha Ray
Keyword(s):  
Endoplasmic Reticulum ◽  
Primary Structure ◽  
Quaternary Structure ◽  
Current Knowledge ◽  
Cellular Function ◽  
Misfolded Proteins ◽  
3 Dimensional ◽  
Normal Cellular Function

The primary structure of polypeptides is converted to their final tertiary and quaternary structure by sequential maturation steps, and the endoplasmic reticulum (ER) provides the environment for the polypeptides to attain their proper 3-dimensional architecture. Proteins that misfold or fail to oligomerize with their partners (Chen et al., 1998; Wileman et al., 1990) are quickly degraded, as unfolded or unassembled proteins could interfere with normal cellular function. Retrotranslocation is the process by which terminally misfolded or unassembled ER proteins are translocated back into the cytosol for degradation mediated by the proteasomal machinery. Increasing amounts of evidence now support the fact that the same translocon pore that is involved in the translocation of polypeptides into the ER is also used for the retrotranslocation process. But questions, like how the misfolded proteins are recognized and targeted to the translocon pore, whether the process requires energy, and what pulls the polypeptides as they emerge out of the pore into the cytoplasm, remain to be elucidated. This review addresses our current knowledge about the retrotranslocation process. 

scholarly journals Algebraic Bayesian Network Secondary Structure Cycles Elimination Based on its Quaternary Structure Analysis

2014 ◽  
Vol 2 (21) ◽  
pp. 143 ◽  
Author(s):  
Andrey Alexandrovich Filchenkov ◽  
Konstantin Vladislavovich Frolenkov ◽  
Alexander Lvovich Tulupyev
Keyword(s):  
Secondary Structure ◽  
Bayesian Network ◽  
Structure Analysis ◽  
Quaternary Structure

Quaternary structure of Limulus polyphemus hemocyanin

1978 ◽  
Vol 36 (2) ◽  
pp. 176-177
Author(s):  
T. Wichertjes ◽  
E.J. Kwak ◽  
E.F.J. Van Bruggen
Keyword(s):  
Electron Microscopy ◽  
Functional Properties ◽  
Horseshoe Crab ◽  
Temperature Jump ◽  
Quaternary Structure ◽  
Crystallographic Analysis ◽  
Limulus Polyphemus ◽  
Oxygen Binding ◽  
X Ray ◽  
Intact Molecule

Hemocyanin of the horseshoe crab (Limulus polyphemus) has been studied in nany ways. Recently the structure, dissociation and reassembly was studied using electron microscopy of negatively stained specimens as the method of investigation. Crystallization of the protein proved to be possible and X-ray crystallographic analysis was started. Also fluorescence properties of the hemocyanin after dialysis against Tris-glycine buffer + 0.01 M EDTA pH 8.9 (so called “stripped” hemocyanin) and its fractions II and V were studied, as well as functional properties of the fractions by NMR. Finally the temperature-jump method was used for assaying the oxygen binding of the dissociating molecule and of preparations of isolated subunits. Nevertheless very little is known about the structure of the intact molecule. Schutter et al. suggested that the molecule possibly consists of two halves, combined in a staggered way, the halves themselves consisting of four subunits arranged in a square.

Characterization of Tamm-Horsfall Urinary Glycoprotein

1973 ◽  
Vol 31 ◽  
pp. 420-421
Author(s):  
John P. Robinson ◽  
J. David Puett
Keyword(s):  
Electron Microscopy ◽  
Circular Dichroism ◽  
Secondary Structure ◽  
Quaternary Structure ◽  
Normal Adult ◽  
Morphological Properties ◽  
Adult Males ◽  
Circular Dichroïsm ◽  
Urinary Glycoprotein

Much work has been reported on the chemical, physical and morphological properties of urinary Tamm-Horsfall glycoprotein (THG). Although it was once reported that cystic fibrotic (CF) individuals had a defective THG, more recent data indicate that THG and CF-THG are similar if not identical.No studies on the conformational aspects have been reported on this glycoprotein using circular dichroism (CD). We examined the secondary structure of THG and derivatives under various conditions and have correlated these results with quaternary structure using electron microscopy.THG was prepared from normal adult males and CF-THG from a 16-year old CF female by the method of Tamm and Horsfall. CF female by the method of Tamm and Horsfall.

Electron Microscopy and image reconstruction reveal the structural basis for spectrin's elastic properties

1992 ◽  
Vol 50 (1) ◽  
pp. 510-511
Author(s):  
Amy M. McGough ◽  
Robert Josephs
Keyword(s):  
Electron Microscopy ◽  
Elastic Properties ◽  
Conformational Changes ◽  
Quaternary Structure ◽  
Three Dimensional ◽  
Membrane Skeleton ◽  
Projection Algorithm ◽  
Structural Basis ◽  
Iterative Approximation ◽  
Membrane Skeletons

The remarkable deformability of the erythrocyte derives in large part from the elastic properties of spectrin, the major component of the membrane skeleton. It is generally accepted that spectrin's elasticity arises from marked conformational changes which include variations in its overall length (1). In this work the structure of spectrin in partially expanded membrane skeletons was studied by electron microscopy to determine the molecular basis for spectrin's elastic properties. Spectrin molecules were analysed with respect to three features: length, conformation, and quaternary structure. The results of these studies lead to a model of how spectrin mediates the elastic deformation of the erythrocyte.Membrane skeletons were isolated from erythrocyte membrane ghosts, negatively stained, and examined by transmission electron microscopy (2). Particle lengths and end-to-end distances were measured from enlarged prints using the computer program MACMEASURE. Spectrin conformation (straightness) was assessed by calculating the particles’ correlation length by iterative approximation (3). Digitised spectrin images were correlation averaged or Fourier filtered to improve their signal-to-noise ratios. Three-dimensional reconstructions were performed using a suite of programs which were based on the filtered back-projection algorithm and executed on a cluster of Microvax 3200 workstations (4).

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