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cowpea virus shell

Bodo D Wilts, Iwan A T Schaap, Christoph F Schmidt
Cowpea chlorotic mottle virus (CCMV) forms highly elastic icosahedral protein capsids that undergo a characteristic swelling transition when the pH is raised from 5 to 7. Here, we performed nano-indentation experiments using an atomic force microscope to track capsid swelling and measure the shells' Young's modulus at the same time. When we chelated Ca(2+) ions and raised the pH, we observed a gradual swelling of the RNA-filled capsids accompanied by a softening of the shell. Control experiments with empty wild-type virus and a salt-stable mutant revealed that the softening was not strictly coupled to the swelling of the protein shells...
May 19, 2015: Biophysical Journal
C A Hommersom, B Matt, A van der Ham, J J L M Cornelissen, N Katsonis
We present the modification of the outer protein shell of cowpea chlorotic mottle virus (CCMV) with linear and strained alkyne groups. These functionalized protein capsids constitute valuable platforms for post-functionalization via click chemistry. After modification, the integrity of the capsid and the reversible disassembly behavior are preserved.
June 28, 2014: Organic & Biomolecular Chemistry
Melanie Brasch, Ilja K Voets, Melissa S T Koay, Jeroen J L M Cornelissen
There has been tremendous progress towards the development of responsive polymers that are programmed to respond to an external stimulus such as light, pH and temperature. The unique combination of molecular packaging followed by slow, controlled release of molecular cargo is of particular importance for self-healing materials and the controlled release of drugs. While much focus and progress remains centred around synthetic carriers, viruses and virus-like particles can be considered ideal cargo carriers as they are intrinsically designed to package, protect and deliver nucleic acid cargo to host cells...
2013: Faraday Discussions
J R Vega-Acosta, R D Cadena-Nava, W M Gelbart, C M Knobler, J Ruiz-García
The self-assembly of many viral capsids is dominated by protein-protein electrostatic interactions. To have a better understanding of this process, it is important to know how the protein and the capsid surface charges vary as a function of the pH and ionic strength. In this work, using phase analysis light scattering, we measured the electrophoretic mobility (EM) of the cowpea chlorotic mottle virus (CCMV), its capsid protein (CP), and a cleaved CP that lacks its basic terminus, as a function of pH and ionic strength...
February 27, 2014: Journal of Physical Chemistry. B
Christoph Globisch, Venkatramanan Krishnamani, Markus Deserno, Christine Peter
The major protective coat of most viruses is a highly symmetric protein capsid that forms spontaneously from many copies of identical proteins. Structural and mechanical properties of such capsids, as well as their self-assembly process, have been studied experimentally and theoretically, including modeling efforts by computer simulations on various scales. Atomistic models include specific details of local protein binding but are limited in system size and accessible time, while coarse grained (CG) models do get access to longer time and length scales but often lack the specific local interactions...
2013: PloS One
J Snijder, I L Ivanovska, M Baclayon, W H Roos, G J L Wuite
The effects of changes in the loading rate during the forced dissociation of single bonds have been studied for a wide variety of interactions. Less is known on the loading rate dependent behaviour of more complex systems that consist of multiple bonds. Here we focus on viral nanoparticles, in particular the protein shell (capsid) that protects the viral genome. As model systems we use the well-studied capsids of the plant virus Cowpea Chlorotic Mottle Virus (CCMV) and of the bacteriophages φ29 and HK97. By applying an atomic force microscopy (AFM) nanoindentation approach we study the loading rate dependency of their mechanical properties...
December 2012: Micron: the International Research and Review Journal for Microscopy
A Janner
The RNA viruses cowpea chlorotic mottle, satellite tobacco mosaic, pariacoto and MS2, already considered in part IV of this series of papers [Janner, A. (2011a), Acta Cryst. A67, 517-520], are investigated further, with the aim to arrive at a possible physical basis for their structural properties. The shell structure of the filled capsid is analyzed in terms of successive spherical boundaries of the sets of icosahedral equivalent chains. By inversion in the sphere enclosing the capsid, the internal boundaries are transformed into external ones, which are more easily visualized...
November 2011: Acta Crystallographica. Section A, Foundations of Crystallography
Choi-Fong Cho, Amber Ablack, Hon-Sing Leong, Andries Zijlstra, John Lewis
Current technologies for tumor imaging, such as ultrasound, MRI, PET and CT, are unable to yield high-resolution images for the assessment of nanoparticle uptake in tumors at the microscopic level(1,2,3,) highlighting the utility of a suitable xenograft model in which to perform detailed uptake analyses. Here, we use high-resolution intravital imaging to evaluate nanoparticle uptake in human tumor xenografts in a modified, shell-less chicken embryo model. The chicken embryo model is particularly well-suited for these in vivo analyses because it supports the growth of human tumors, is relatively inexpensive and does not require anesthetization or surgery 4,5...
2011: Journal of Visualized Experiments: JoVE
Eric R May, Ankush Aggarwal, William S Klug, Charles L Brooks
The long wavelength, low-frequency modes of motion are the relevant motions for understanding the continuum mechanical properties of biomolecules. By examining these low-frequency modes, in the context of a spherical harmonic basis set, we identify four elastic moduli that are required to describe the two-dimensional elastic behavior of capsids. This is in contrast to previous modeling and theoretical studies on elastic shells, which use only the two-dimensional Young's modulus (Y) and the bending modulus (κ) to describe the system...
June 8, 2011: Biophysical Journal
Ruben D Cadena-Nava, Yufang Hu, Rees F Garmann, Benny Ng, Alexander N Zelikin, Charles M Knobler, William M Gelbart
The inside surfaces of the protein shells of many viruses are positively charged, thereby enhancing the self-assembly of capsid proteins around their (oppositely charged) RNA genome. These proteins have been shown to organize similarly around a variety of nonbiological, negatively charged, polymers, for example, poly(styrene sulfonate) (PSS), forming virus-like particles (VLPs). We have demonstrated recently that the VLPs formed from cowpea chlorotic mottle virus (CCMV) capsid protein increase in size (from T=2 to T=3 structures) upon increase in PSS molecular weight (from 400 kDa to 3...
March 17, 2011: Journal of Physical Chemistry. B
Jeroen Pouwels, Jan E Carette, Jan Van Lent, Joan Wellink
SUMMARY Taxonomy: Cowpea mosaic virus (CPMV) is the type member of the Comoviridae and bears a strong resemblance to animal picornaviruses, both in gene organization and in the amino acid sequence of replication proteins. Little systematic work has been done to compare isolates of the virus from different parts of the world. Physical properties: Purified preparations of virus contain three centrifugal components; empty protein shells without RNA (T) and two nucleoprotein components (M and B), containing 24% and 34% RNA, respectively...
November 1, 2002: Molecular Plant Pathology
Peter Prinsen, Paul van der Schoot, William M Gelbart, Charles M Knobler
Under conditions of low ionic strength and a pH ranging between about 3.7 and 5.0, solutions of purified coat proteins of cowpea chlorotic mottle virus (CCMV) form spherical multishell structures in the absence of viral RNA. The outer surfaces of the shells in these structures are negatively charged, whereas the inner surfaces are positively charged due to a disordered cationic N-terminal domain of the capsid protein, the arginine-rich RNA-binding motif that protrudes into the interior. We show that the main forces stabilizing these multishells are counterion release combined with a lower charge density in the RNA-binding motif region of the outer shells due to their larger radii of curvature, arguing that these compensate for the outer shells not being able to adopt the smaller, optimal, radius of curvature of the inner shell...
April 29, 2010: Journal of Physical Chemistry. B
Inge J Minten, Linda J A Hendriks, Roeland J M Nolte, Jeroen J L M Cornelissen
Multiple proteins can be bound within the Cowpea Chlorotic Mottle Virus capsid shell in an efficient and controlled manner by using heterodimeric coiled-coil peptide oligomers. Through genetic modification, these oligomers can be attached to the capsid protein and an enhanced green fluorescent protein (EGFP). In this way, the capsid proteins can be noncovalently bound to EGFP prior to the induction of the capsid assembly. Up to 15 EGFP proteins can be encapsulated per capsid in a controlled and efficient manner...
December 16, 2009: Journal of the American Chemical Society
L Lavelle, M Gingery, M Phillips, W M Gelbart, C M Knobler, R D Cadena-Nava, J R Vega-Acosta, L A Pinedo-Torres, J Ruiz-Garcia
We present an experimental study of the self-assembly of capsid proteins of the cowpea chlorotic mosaic virus (CCMV), in the absence of the viral genome, as a function of pH and ionic strength. In accord with previous measurements, a wide range of polymorphs can be identified by electron microscopy, among them single and multiwalled shells and tubes. The images are analyzed with respect to size and shape of aggregates, and evidence is given that equilibrium has been achieved, allowing a phase diagram to be constructed...
March 26, 2009: Journal of Physical Chemistry. B
Nicole F Steinmetz, Marianne Manchester
PEGylation is an effective strategy for reducing biospecific interactions for pharmaceuticals. The plant virus Cowpea mosaic virus (CPMV) has been studied for potential nanobiomedical applications by virtue of its natural interactions with mammalian endothelial cells. To investigate the degree of PEGylation required to retarget CPMV-based formulations to other destinations, two CPMV-PEG formulations, CPMV-PEG1000 (P1) and CPMV-PEG2000 (P2) were tested. Modeling suggested that the PEG chains were displayed as flattened mushrooms on the particle with an estimated surface grafting area of 0...
April 13, 2009: Biomacromolecules
Connie B Chang, Charles M Knobler, William M Gelbart, Thomas G Mason
Virus-like particles are biomimetic delivery vehicles that cloak nanoscale cores inside coatings of viral capsid proteins, offering the potential for protecting their contents and targeting them to particular tissues and cells. To date, encapsidation has been demonstrated only for a relatively limited variety of core materials, such as compressible polymers and facetted nanocrystals, over a narrow range of cores sizes and of pH and ionic strength. Here, we encapsidate spherical nanodroplets of incompressible oil stabilized by adsorbed anionic surfactant using cationic capsid protein purified from cowpea chlorotic mottle virus...
February 2008: ACS Nano
Mathias Buenemann, Peter Lenz
The elasticity and mechanical stability of empty and filled viral capsids under external force loading are studied in a combined analytical and numerical approach. We analyze the influence of capsid structure and chirality on the mechanical properties. We find that generally skew shells have lower stretching energy. For large Föppl-von Kármán numbers gamma (gamma approximately 10(5)), skew structures are stiffer in their elastic response than nonchiral ones. The discrete structure of the capsules not only leads to buckling for large gamma but also influences the breakage behavior of capsules below the buckling threshold: the rupture force shows a gamma1/4 scaling rather than a gamma1/2 scaling as expected from our analytical results for continuous shells...
November 2008: Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
T Schmidt, J E Johnson, W E Phillips
The X-ray diffraction patterns of the four components of cowpea mosaic virus isolated from a cesium chloride gradient were measured, using film methods, to 30 A resolution. Diffraction patterns were analyzed by fitting computed two-shell spherical models to the observed data. The fitting procedure was applied to data to 80 A resolution to avoid the nonspherical contribution to the pattern observed at higher resolution. At pH 7.0 all four components displayed the same external spherically averaged radius of 140 +/-2 A...
May 1983: Virology
Melissa M Gibbons, William S Klug
A series of recent nanoindentation experiments on the protein shells (capsids) of viruses has established atomic force microscopy (AFM) as a useful framework for probing the mechanics of large protein assemblies. Specifically these experiments provide an opportunity to study the coupling of the global assembly response to local conformational changes. AFM experiments on cowpea chlorotic mottle virus, known to undergo a pH-controlled swelling conformational change, have revealed a pH-dependent mechanical response...
October 2008: Biophysical Journal
Mathias Buenemann, Peter Lenz
We studied the elastic properties and mechanical stability of viral capsids under external force-loading with computer simulations. Our approach allows the implementation of specific geometries corresponding to specific phages, such as phi29 and cowpea chlorotic mottle virus. We demonstrate how, in a combined numerical and experimental approach, the elastic parameters can be determined with high precision. The experimentally observed bimodality of elastic spring constants is shown to be of geometrical origin, namely the presence of pentavalent units in the viral shell...
June 12, 2007: Proceedings of the National Academy of Sciences of the United States of America
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