Nav: Home

Perfecting a viral pack mule

March 29, 2016

LA JOLLA, CA - March 29, 2016 - Viruses aren't always bad. In fact, scientists can harness the capabilities of some viruses for good--modifying the viruses to carry drug molecules, for example.

One useful virus has been cowpea mosaic virus (CPMV), a plant pathogen that can be modified to aid in tumor detection and even chemotherapy.

In a new study, published online ahead of print in the journal Structure, researchers at The Scripps Research Institute (TSRI) report that, based on its structure, a hollowed-out version of CPMV could also be effective in human therapies.

"By studying the structure of the viral particles, we can get important information for transforming this plant virus into a useful therapeutic," said TSRI Associate Professor Vijay Reddy, senior author of the study.

An 'Empty' Virus

TSRI researchers have studied CPMV for decades. In fact, the structure of the virus was first determined in the lab of TSRI Professor Jack Johnson, who also served as a co-author on the new study.

CPMV is an especially useful drug delivery agent because it has about 300 different sites on its external and internal surfaces where researchers can attach molecules. Because CPMV is a plant virus, it is harmless to humans. To eliminate any lingering concerns of viral genomes entering the human body, scientists have created "empty" versions of CPMV, called eVLPs (empty virus-like particles), which lack the virus's genetic material.

"The eVLP is no longer a virus; it is just a protein capsule," explained Reddy.

The question has been whether eVLPs of CPMV retain the same structure in the absence of viral genome as natural CPMV viral particles.

Able to Carry the Load

In the new study, Reddy and his colleagues used an imaging technique called x-ray crystallography to create a high-resolution image of the 3D structure of CPMV eVLPs.

The image showed the structures of eVLP particles are very similar to CPMV particles, giving scientists the go-ahead to use the same modification strategies on both. This finding was in sync with a previous study showing eVLPs at a lower resolution.

The current study also revealed a new detail on both eVLPs and CPMV virus particles. Mass-spectrometry-based proteomics analysis identified multiple proteolytic cleavage sites--a spot where amino acids are cut off--on one of the proteins on the particle surface. Previous research had indicated only one such cleavage site in this region, not three. With the new information, researchers know not to add crucial molecules to those amino acids in case they get clipped off too.

Reddy said the new study opens the door to future research on using eVLPs to carry drug molecules and designing customized vaccines.
-end-
In addition to Reddy and Johnson, authors of the study, "Crystal structure and proteomics analysis of empty virus-like particles of Cowpea mosaic virus," were Nhung T. Huynh (first author), You-Chan Ku and Linh T. Hoang of TSRI; Emma L. Hesketh and Neil A. Ranson of the University of Leeds; and Pooja Saxena, Yulia Meshcheriakova and George P. Lomonossoff of the John Innes Centre, Norwich Research Park, UK.

This research was supported by the National Institutes of Health (NIH, grants AI070771, Y1-CO-1020 and Y1-GN-11040), the U.S. Department of Energy (contract DE-AC02-06CH11357), UK Biotechnological and Biological Sciences Research Council (BBSRC, grant BB/L020955/1), The BBSRC Institute Strategic Programme Grant "Understanding and Exploiting Plant and Microbial Secondary Metabolism" (grant BB/J004596/1) and the John Innes Foundation.

Scripps Research Institute

Related Amino Acids Articles:

Simulating amino acid starvation may improve dengue vaccines
In a new paper in Science Signaling, researchers at the University of Hyderabad in India and the Cornell University College of Veterinary Medicine show that a plant-based compound called halofuginone improves the immune response to a potential vaccine against dengue virus.
CoP-electrocatalytic reduction of nitroarenes: a controllable way to azoxy-, azo- and amino-aromatic
The development of a green, efficient and highly controllable manner to azoxy-, azo- and amino-aromatics from nitro-reduction is extremely desirable both from academic and industrial points of view.
Origin of life insight: peptides can form without amino acids
Peptides, one of the fundamental building blocks of life, can be formed from the primitive precursors of amino acids under conditions similar to those expected on the primordial Earth, finds a new UCL study published in Nature.
Metabolic reprogramming of branched-chain amino acid facilitates drug resistance in lung cancer
Research teams led by Dr. Ji Hongbin at the Institute of Biochemistry and Cell Biology of the Chinese Academy of Sciences, Dr.
Researchers develop fast, efficient way to build amino acid chains
Researchers report that they have developed a faster, easier and cheaper method for making new amino acid chains -- the polypeptide building blocks that are used in drug development and industry -- than was previously available.
Characterisation of the structure of a member of the L-Amino acid Transporter (LAT) family
Mutations in L-amino acid transporters (LATs) can lead to a wide range of conditions, such as autism, hearing loss and aminoacidurias.
Model learns how individual amino acids determine protein function
A machine-learning model from MIT researchers computationally breaks down how segments of amino acid chains determine a protein's function, which could help researchers design and test new proteins for drug development or biological research.
Starving leukemia cells by targeting amino acids
Eliminating ASCT2 selectively stops the growth of leukemia cells, while having limited effects on healthy blood cells and hematopoetic (blood-forming) stem cells.
Unveiling the role of selenocysteine, the mysterious 21st amino acid
Selenocysteine is an essential amino acid for certain species, such as humans and the other vertebrates, although it has disappeared from others, such as insects.
Novel electron microscopy offers nanoscale, damage-free isotope tracking in amino acids
A new electron microscopy technique that detects the subtle changes in the weight of proteins at the nanoscale -- while keeping the sample intact -- could open a new pathway for deeper, more comprehensive studies of the basic building blocks of life.
More Amino Acids News and Amino Acids Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

In & Out Of Love
We think of love as a mysterious, unknowable force. Something that happens to us. But what if we could control it? This hour, TED speakers on whether we can decide to fall in — and out of — love. Guests include writer Mandy Len Catron, biological anthropologist Helen Fisher, musician Dessa, One Love CEO Katie Hood, and psychologist Guy Winch.
Now Playing: Science for the People

#543 Give a Nerd a Gift
Yup, you guessed it... it's Science for the People's annual holiday episode that helps you figure out what sciency books and gifts to get that special nerd on your list. Or maybe you're looking to build up your reading list for the holiday break and a geeky Christmas sweater to wear to an upcoming party. Returning are pop-science power-readers John Dupuis and Joanne Manaster to dish on the best science books they read this past year. And Rachelle Saunders and Bethany Brookshire squee in delight over some truly delightful science-themed non-book objects for those whose bookshelves are already full. Since...
Now Playing: Radiolab

An Announcement from Radiolab