scholarly journals Investigating the structural basis of purine specificity in the structures of MS2 coat protein RNA translational operator hairpins

2002 ◽  
Vol 30 (12) ◽  
pp. 2678-2685 ◽  
Author(s):  
C. Helgstrand
Keyword(s):  
Coat Protein ◽  
Structural Basis ◽  
Translational Operator

PRR1 coat protein binding to its RNA translational operator

2013 ◽  
Vol 69 (3) ◽  
pp. 367-372 ◽  
Author(s):  
Magnus Persson ◽  
Kaspars Tars ◽  
Lars Liljas
Keyword(s):  
Coat Protein ◽  
Protein Binding ◽  
Translational Operator

scholarly journals Coat–protein–mediated resistance to tobacco mosaic virus: discovery mechanisms and exploitation

1999 ◽  
Vol 354 (1383) ◽  
pp. 659-664 ◽  
Author(s):  
Roger N. Beachy
Keyword(s):  
Coat Protein ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Structural Basis ◽  
Challenge Virus ◽  
Transgenic Cell ◽  
Coat Protein Mediated Resistance ◽  
Local Cell

In 1986 we reported that transgenic plants which accumulate the coat protein of tobacco mosaic virus (TMV) are protected from infection by TMV, and by closely related tobamoviruses. The phenomenon is referred to as coat–protein–mediated resistance (CP–MR), and bears certain similarities to cross protection, a phenomenon described by plant pathologists early in this century. Our studies of CP–MR against TMV have demonstrated that transgenically expressed CP interferes with disassembly of TMV particles in the inoculated transgenic cell. However, there is little resistance to local, cell–to–cell spread of infection. CP–MR involves interaction between the transgenic CP and the CP of the challenge virus, and resistance to TMV is greater than to tobamoviruses that have CP genes more distantly related to the transgene. Using the known coordinates of the three–dimensional structure of TMV we developed mutant forms of CP that have stronger inter–subunit interactions, and confer increased levels of CP–MR compared with wild–type CP. Similarly, it is predicted that understanding the cellular and structural basis of CP–MR will lead to the development of variant CP transgenes that each can confer high levels of resistance against a range of tobamoviruses.

scholarly journals Evidence that a chaperone–usher-like pathway of Myxococcus xanthus functions in spore coat formation

Microbiology ◽  
2011 ◽  
Vol 157 (7) ◽  
pp. 1886-1896 ◽  
Author(s):  
Xiaoyan Leng ◽  
Wei Zhu ◽  
Jing Jin ◽  
Xiaohua Mao
Keyword(s):  
Amino Acid ◽  
Coat Protein ◽  
Myxococcus Xanthus ◽  
Surface Structures ◽  
Structural Basis ◽  
Spore Coat ◽  
Sequence Comparisons ◽  
Morphological Alterations ◽  
Secretion Pathway ◽  
Spore Coat Protein

Many bacteria use the chaperone–usher (CU) secretion pathway to assemble on their surfaces typical or atypical fimbrial organelles. Four consecutive genes of Myxococcus xanthus DK1622, MXAN3885–3882, were predicted to constitute an operon encoding a CU-like system involved in the assembly of the spore coat; however, experimental evidence supporting this hypothesis was lacking. In this study, co-transcription of MXAN3885–3883 was verified, and we found that this operon was expressed 12–15 h after initiation of M. xanthus development under conditions of stringent starvation. The MXAN3885 protein, which is highly homologous to, but expressed earlier than, the spore coat protein U of another M. xanthus strain, DZF1, was present mainly on the outer surface of myxospores. Inactivation of MXAN3883, encoding a putative outer membrane usher, inhibited assembly of MXAN3885 protein on spore surfaces and caused certain morphological alterations in the spore coat. Hence, the CU-like pathway in M. xanthus indeed functions in spore coat biogenesis. Based on chaperone amino acid sequence comparisons, our analysis suggests that the structural basis of the M. xanthus CU-like pathway for spore coat assembly may be different from that of most surface structures assembled by classical CU systems.

scholarly journals The structure of a plant-specific partitivirus capsid reveals a unique coat protein domain architecture with an intrinsically disordered protrusion

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Matthew Byrne ◽  
Aseem Kashyap ◽  
Lygie Esquirol ◽  
Neil Ranson ◽  
Frank Sainsbury
Keyword(s):  
Coat Protein ◽  
Domain Architecture ◽  
Plant Viruses ◽  
Protein Domain ◽  
Wild Plants ◽  
Structural Basis ◽  
Coat Proteins ◽  
Intrinsically Disordered ◽  
Binding Interface ◽  
Protein Dimers

AbstractPersistent plant viruses may be the most common viruses in wild plants. A growing body of evidence for mutualism between such viruses and their hosts, suggests that they play an important role in ecology and agriculture. Here we present the capsid structure of a plant-specific partitivirus, Pepper cryptic virus 1, at 2.9 Å resolution by Cryo-EM. Structural features, including the T = 1 arrangement of 60 coat protein dimers, are shared with fungal partitiviruses and the picobirnavirus lineage of dsRNA viruses. However, the topology of the capsid is markedly different with protrusions emanating from, and partly comprising, the binding interface of coat protein dimers. We show that a disordered region at the apex of the protrusion is not required for capsid assembly and represents a hypervariable site unique to, and characteristic of, the plant-specific partitiviruses. These results suggest a structural basis for the acquisition of additional functions by partitivirus coat proteins that enables mutualistic relationships with diverse plant hosts.

scholarly journals Structure of a Plant-Specific Partitivirus Capsid Reveals a Novel Coat Protein Architecture with a Hypervariable Protrusion

2021 ◽  
Author(s):  
Matthew Byrne ◽  
Aseem Kashyap ◽  
Lygie Esquirol ◽  
Neil Ranson ◽  
Frank Sainsbury
Keyword(s):  
Coat Protein ◽  
Structural Features ◽  
Plant Viruses ◽  
Wild Plants ◽  
Structural Basis ◽  
Coat Proteins ◽  
Protein Architecture ◽  
Binding Interface ◽  
Protein Dimers ◽  
Site Characteristic

SUMMARYPersistent plant viruses may be the most common viruses in wild plants. A growing body of evidence for mutualism between such viruses and their hosts, suggests that they play an important role in ecology and agriculture. Here we present the structure of a plant-specific partitivirus capsid at 2.9 Å resolution by Cryo-EM. Structural features, including the T=1 arrangement of 60 coat protein dimers, are shared with fungal partitiviruses and the picobirnavirus lineage of dsRNA viruses. However, the topology of the capsid is markedly different with protrusions emanating from, and partly comprising, the binding interface of coat protein dimers. We show that a disordered region at the apex of the protrusion is not required for capsid assembly and represents a hypervariable site characteristic of the plant-specific partitiviruses. These results suggest a structural basis for the acquisition of additional functions by partitivirus coat proteins that enables mutualistic relationships with diverse plant hosts.

scholarly journals Structural basis for the multitasking nature of the potato virus Y coat protein

2019 ◽  
Vol 5 (7) ◽  
pp. eaaw3808 ◽  
Author(s):  
Andreja Kežar ◽  
Luka Kavčič ◽  
Martin Polák ◽  
Jiří Nováček ◽  
Ion Gutiérrez-Aguirre ◽  
...  
Keyword(s):  
Coat Protein ◽  
Potato Virus ◽  
Atomic Structure ◽  
Plant Pathogens ◽  
Potato Virus Y ◽  
Mutational Analysis ◽  
Structural Basis ◽  
In Planta ◽  
Virus Like Particles ◽  
Carboxyl Terminal

Potato virus Y (PVY) is among the most economically important plant pathogens. Using cryoelectron microscopy, we determined the near-atomic structure of PVY’s flexuous virions, revealing a previously unknown lumenal interplay between extended carboxyl-terminal regions of the coat protein units and viral RNA. RNA–coat protein interactions are crucial for the helical configuration and stability of the virion, as revealed by the unique near-atomic structure of RNA-free virus-like particles. The structures offer the first evidence for plasticity of the coat protein’s amino- and carboxyl-terminal regions. Together with mutational analysis and in planta experiments, we show their crucial role in PVY infectivity and explain the ability of the coat protein to perform multiple biological tasks. Moreover, the high modularity of PVY virus-like particles suggests their potential as a new molecular scaffold for nanobiotechnological applications.

Organization of tight junctions in the choroid plexus epithelium

1978 ◽  
Vol 36 (2) ◽  
pp. 336-337
Author(s):  
B. Van Deurs ◽  
J. K. Koehler
Keyword(s):  
Choroid Plexus ◽  
Present Report ◽  
Freeze Fracture ◽  
Barrier Properties ◽  
Cell Junctions ◽  
Structural Basis ◽  
Apical Surface ◽  
Choroid Plexus Epithelium ◽  
Solid Nitrogen ◽  
Special Composition

The choroid plexus epithelium constitutes a blood-cerebrospinal fluid (CSF) barrier, and is involved in regulation of the special composition of the CSF. The epithelium is provided with an ouabain-sensitive Na/K-pump located at the apical surface, actively pumping ions into the CSF. The choroid plexus epithelium has been described as “leaky” with a low transepithelial resistance, and a passive transepithelial flux following a paracellular route (intercellular spaces and cell junctions) also takes place. The present report describes the structural basis for these “barrier” properties of the choroid plexus epithelium as revealed by freeze fracture.Choroid plexus from the lateral, third and fourth ventricles of rats were used. The tissue was fixed in glutaraldehyde and stored in 30% glycerol. Freezing was performed either in liquid nitrogen-cooled Freon 22, or directly in a mixture of liquid and solid nitrogen prepared in a special vacuum chamber. The latter method was always used, and considered necessary, when preparations of complementary (double) replicas were made.

High resolution spot scan imaging of frozen, hydrated actin bundles with 400kV electrons

1992 ◽  
Vol 50 (1) ◽  
pp. 512-513
Author(s):  
J. Jakana ◽  
M.F. Schmid ◽  
P. Matsudaira ◽  
W. Chiu
Keyword(s):  
High Resolution ◽  
Binding Proteins ◽  
Actin Binding ◽  
Eukaryotic Cells ◽  
Dimensional Structure ◽  
Structural Basis ◽  
Actin Bundle ◽  
Actin Bundles ◽  
3 Dimensional ◽  
Macromolecular Assembly

Actin is a protein found in all eukaryotic cells. In its polymerized form, the cells use it for motility, cytokinesis and for cytoskeletal support. An example of this latter class is the actin bundle in the acrosomal process from the Limulus sperm. The different functions actin performs seem to arise from its interaction with the actin binding proteins. A 3-dimensional structure of this macromolecular assembly is essential to provide a structural basis for understanding this interaction in relationship to its development and functions.

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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