First structure of a DNA crosslink repair ligase determined

Diamond’s Electron Bio-Imaging Facility (eBIC) has been used to generate the first 3D structure of the Fanconi anaemia (FA) core complex, a multi-subunit E3 ubiquitin ligase required for the repair of damaged DNA. The work, led by Dr Lori Passmore from the MRC Laboratory of Molecular Biology and a team of researchers, has been published today in Nature, and their research provides the molecular architecture of the FA core complex and new insights into how the complex functions.

The FA pathway senses and repairs DNA crosslinks that occur after exposure to chemicals including chemotherapeutic agents and alcohol, but also as a result of normal cellular metabolism. The megadalton FA core complex acts as an E3 ubiquitin ligase to initiate removal of these DNA crosslinks, helping to repair the damage caused. The research team used eBIC’s imaging facilities to make a major breakthrough in understanding the FA core complex by determining its structure using an integrative approach including cryo-electron microscopy and mass spectrometry.

Dr Peijun Zhang, Director of eBIC notes that:

Enabling cutting-edge research like this is exactly why we established eBIC, to provide scientists with state-of-the-art experimental equipment and expertise in the field of cryo-electron microscopy, for both single particle analysis and cryo-electron tomography. Determining the structure of the FA core complex for the first time is a fantastic achievement for the MRC research team.

>Read more on the Diamond Light Source website

Image: The FA core complex.
Credit: Phospho Biomedical Animation

Study offers new target for antibiotic resistant bacteria

As antibiotic resistance rises, the search for new antibiotic strategies has become imperative. In 2013, the Centers for Disease Control estimated that antibiotic resistant bacteria cause at least 2 million infections and 23,000 deaths a year in the U.S.; a recent report raised the likely mortality rate to 162,044.
New Cornell research on an enzyme in bacteria essential to making DNA offers a new pathway for targeting pathogens. In “Convergent Allostery in Ribonucleotide Reductase,” published June 14 in Nature Communications, researchers used the MacCHESS research stations at the Cornell High Energy Synchrotron Source (CHESS) to reveal an unexpected mechanism of activation and inactivation in the protein ribonucleotide reductase (RNR).

Understanding the “switch” that turns RNR off provides a possible means to shut off the reproduction of harmful bacteria.
RNRs take ribonucleotides, the building blocks of RNA, and convert them to deoxyribonucleotides, the building blocks of DNA. In all organisms, the regulation of RNRs involves complex mechanisms, and for good reason: These mechanisms prevent errors and dangerous mutations.

>Read more on the CHESS website

Image: William Thomas, a graduate student in the field of chemistry and chemical biology, collects data on ribonucleotide reductase.

Construction starts on new Cryo-EM center

Called the Laboratory of BioMolecular Structure, the new cryo-electron microscope center will offer world-leading imaging capabilities for life sciences research.

Today, the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory broke ground on the Laboratory of BioMolecular Structure (LBMS), a state-of-the-art research center for life science imaging. At the heart of the center will be two new NY-State-funded cryo-electron microscopes (cryo-EM) specialized for studying biomaterials, such as complex protein structures.

“Cryo-electron microscopy is a rapidly-advancing imaging technique that is posting impressive results on a weekly basis,” said LBMS Director Sean McSweeney. “The mission of LBMS is to advance the scientific understanding of key biological processes and fundamental molecular structures.”

“Throughout my career, I have worked hard to make our region of the State a high-tech hub, bringing together the talents and expertise of scientists and facilities across Long Island.  I am pleased to have played a part in the creation of the new cryo-EM center, which will add to the incredible facilities at Brookhaven National Lab and enable our scientific community to lead the way in world-class imaging research and discovery,” said NY State Senator Ken LaValle.

>Read more on the NSLS-II at BNL website

Image: New York State Senator Ken LaValle joined leaders of Empire State Development and Brookhaven Lab for the LBMS groundbreaking ceremony. Pictured from left to right are Jim Misewich (Associate Laboratory Director for Energy and Photon Sciences, Brookhaven Lab), Erik Johnson (NSLS-II Deputy for Construction), Sean McSweeney (LBMS Director and NSLS-II Structural Biology Program Manager), Robert Gordon (DOE-Brookhaven Site Office Manager), Ken LaValle, Cara Longworth (Regional Director, Empire State Development), Danah Alexander (Senior Project Manager, Empire State Development), and John Hill (NSLS-II Director).

Secrets of the deadly white-tail virus revealed

The inner workings of a lethal giant freshwater prawn virus have been revealed by an international team of researchers using data gathered at Diamond Light Source. The results reveal a possible new class of virus and presents the prospect of tackling a disease that can devastate prawn farms around the world.

The detailed structure of a virus that can devastate valuable freshwater prawn fisheries has been revealed by an international team using image data collected in the Electron Bio-Imaging Centre (eBIC) based at Diamond Light Source. The researchers produced high-resolution images of virus like particles, VLP’s, composed of virus shell proteins which they compared with lower resolution images of the complete virus purified from prawn larvae. They found strong similarities between the two suggesting that the more detailed VLP images are a good representation of the intact virus. This research, exposing the inner workings of the MrNV, could make it easier to develop ways of combating the economically important disease, but also suggests that it belongs in a new, separate, group of nodaviruses.
The researchers used the rapidly developing technique of cryo-electron microscopy, cryoEM, which has the ability to produce very high-resolution images of frozen virus particles. Images so detailed that the positions of individual atoms could be inferred. Recent breakthroughs in this technique have transformed the study of relatively large biological complexes like viruses allowing researchers to determine their structures comparatively quickly. The data to produce the MrNV structure described here was captured in two days at the eBIC facility.

>Read more on the Diamond Light Source website

Image: 3D model of the MrNV
Credit: Dr David Bhella

Fighting malaria with X-rays

Today 25 April, is World Malaria Day.

Considered as one of humanity’s oldest life-threatening diseases, nearly half the world population is at risk, with 216 million people affected in 91 countries worldwide in 2016. Malaria causes 445 000 deaths every year, mainly among children. The ESRF has been involved in research into Malaria since 2005, with different techniques being used in the quest to find ways to prevent or cure the disease.

Malaria in humans is caused by Plasmodium parasites, the greatest threat coming from two species: P. falciparum and P. vivax. The parasites are introduced through the bites of infected female Anopheles mosquitoes. They travel to the liver where they multiply, producing thousands of new parasites. These enter the blood stream and invade red blood cells, where they feed on hemoglobin (Hgb) in order to grow and multiply. After creating up to 20 new parasites, the red blood cells burst, releasing daughter parasites ready for new invasions. This life cycle leads to an exponential growth of infected red blood cells that may cause the death of the human host.

The research carried out over the years at the ESRF has aimed to identify mechanisms critical for the parasite’s survival in the hope of providing an intelligent basis for the development of drugs to stop the parasite’s multiplication and spread.

>Read more on the European Synchrotron website

Image: Inside the experimental hutch of the ESRF’s ID16A nano-analysis beamlin.
Credit: Pierre Jayet