Analyzing poppies to make better drugs

A team of researchers from the University of Calgary has uncovered new information about a class of plant enzymes that could have implications for the pharmaceutical industry. In a paper published in the Journal of Biological Chemistry, the scientists explain how they revealed molecular details of an enzyme class that is central to the synthesis of many widely used pharmaceuticals, including the painkillers codeine and morphine.  

The team used the Canadian Light Source at the University of Saskatchewan and the SLAC National Accelerator Laboratory to better understand how the enzyme behaves, which is crucial for unleashing its potential to make novel medicines. “Until this study, we didn’t know the key structural details of the enzyme. We learned from the structure of the enzyme bound to the product how the methylation reaction locks the product into a certain stereochemistry. It was completely unknown how the enzyme did that before we determined this structure,” corresponding author Dr. Kenneth Ng explained.

Stereochemistry is an important concept when it comes to safety and efficacy in drug design. A molecule can have a few different arrangements—similar to how your left hand is a mirror image of your right hand. These arrangements can lead to very different effects.

>Read more on the Canadian Light Source website

Image: group photo of some of the researchers involved with this project. From left to right: Ken Ng (Professor and corresponding author), Jeremy Morris (PhD graduate and second author), Dean Lang (PhD student and first author), and Peter Facchini (Professor, CSO of Willow Biosciences and senior author).

A new generation of anti-malaria drugs


Malaria is endemic to large areas of Africa, Asia and South America and annually kills more than 400,000 people, a majority of whom are children under age 5, with hundreds of millions of new infections every year. Although artemisinin-based drug combinations are available to treat malaria, reports from Southeast Asia of treatment failures are raising concerns about drug resistance spreading to Africa. Fortunately, there is hope on the horizon because there are several new antimalarial drug candidates undergoing clinical testing as well as other promising drug targets that are under investigation.
An international research team has for the first time determined the atomic structure of a protein kinase called PKG in Plasmodium parasites that cause malaria—a finding that potentially will help create a new generation of anti-malarial drugs and advance fundamental research. PKG[i] plays essential roles in the developmental stages of the parasite’s complex life cycle, so understanding its structure is key to developing malaria-fighting therapies that specifically target PKG and not other human enzymes, according to researcher Dr. Charles Calmettes.

>Read more on the Canadian Light Source website

Image: PKG crystal.

Preventing tumour metastasis

Researchers at the Paul Scherrer Institute, together with colleagues from the pharmaceutical company F. Hoffmann-La Roche AG, have taken an important step towards the development of an agent against the metastasis of certain cancers.

Using the Swiss Light Source, they deciphered the structure of a receptor that plays a crucial role in the migration of cancer cells. This makes it possible to identify agents that could prevent the spread of certain cancer cells via the body’s lymphatic system. The researchers have now published their results in the journal Cell.
When cancer cells spread in the body, secondary tumours, called metastases, can develop. These are responsible for around 90 percent of deaths in cancer patients. An important pathway for spreading the cancer cells is through the lymphatic system, which, like the system of blood vessels, runs through the entire body and connects lymph nodes to each other. In the migration of white blood cells through this system, for example to coordinate the defense against pathogens, one special membrane protein, the chemokine receptor 7 (CCR7) plays an important role. It sits in the shell of the cells, the cell membrane, in such a way that it can receive external signals and relay them to the interior. Within the framework of a joint project with the pharmaceutical company F. Hoffmann-La Roche AG (Roche), researchers at the Paul Scherrer Institute (PSI) have for the first time been able to decipher the structure of CCR7 and lay the foundation for the development of a drug that could prevent metastasis in certain prevalent cancer types, such as colorectal cancer.

Read more on the SLS at PSI website

Image: Steffen Brünle (right) and Jörg Standfuss at the apparatus they use to separate proteins from each other. For their study, the researchers modified insect cells to produce a human protein. To extract this from the cell, the cell was destroyed, and then the protein, whose structure the researchers have now elucidated, was separated with the help of this apparatus.
Credit: Paul Scherrer Institute/Markus Fischer

Collaboration develops sensitive data protocol

MAX IV pairs up with Sprint Bioscience, a listed drug development company, in a new project to improve how companies can benefit from new, faster X-ray fragment screening experiments, while still protecting their valuable information during analysis at FragMAX.

Recently, the project was granted with 500 000 SEK from Sweden’s innovation agency Vinnova.
More or less, all pharmaceutical drugs are molecules binding to proteins in your body. When doing this, they either initiate or inhibit the process in which the target protein is involved. Proteins are in charge of everything from cells dividing at the right moment to the metabolism of the food you eat or signaling in the brain.

>Read more on the MAX IV website

Image: Sample holders
Credit: Ben Libberton

New approach for solving protein structures from tiny crystals

Technique opens door for studies of countless hard-to-crystallize proteins involved in health and disease

Using x-rays to reveal the atomic-scale 3-D structures of proteins has led to countless advances in understanding how these molecules work in bacteria, viruses, plants, and humans—and has guided the development of precision drugs to combat diseases such as cancer and AIDS. But many proteins can’t be grown into crystals large enough for their atomic arrangements to be deciphered. To tackle this challenge, scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and colleagues at Columbia University have developed a new approach for solving protein structures from tiny crystals.

The method relies on unique sample-handling, signal-extraction, and data-assembly approaches, and a beamline capable of focusing intense x-rays at Brookhaven’s National Synchrotron Light Source II (NSLS-II)—a DOE Office of Science user facility—to a millionth-of-a-meter spot, about one-fiftieth the width of a human hair.

>Read more on the NSLS-II at Brookhaven Lab website

Image: Wuxian Shi, Martin Fuchs, Sean McSweeney, Babak Andi, and Qun Liu at the FMX beamline at Brookhaven Lab’s National Synchrotron Light Source II, which was used to determine a protein structure from thousands of tiny crystals.

Researchers create the first maps of two melatonin receptors essential for sleep

A better understanding of how these receptors work could enable scientists to design better therapeutics for sleep disorders, cancer and Type 2 diabetes.

An international team of researchers used an X-ray laser at the Department of Energy’s SLAC National Accelerator Laboratory to create the first detailed maps of two melatonin receptors that tell our bodies when to go to sleep or wake up, and guide other biological processes. A better understanding of how they work could enable researchers to design better drugs to combat sleep disorders, cancer and Type 2 diabetes. Their findings were published in two papers today in Nature.

The team, led by the University of Southern California, used X-rays from SLAC’s Linac Coherent Light Source (LCLS) to map the receptors, MT1 and MT2, bound to four different compounds that activate them: an insomnia drug, a drug that mixes melatonin with the antidepressant serotonin, and two melatonin analogs.

>Read more on the LCLS at SLAC website

Image: The researchers showed that both melatonin receptors contain narrow channels embedded in the cell’s fatty membranes. These channels only allow melatonin, which can exist happily in both water and fat, to pass through, preventing serotonin, which has a similar structure but is only happy in watery environments, from binding to the receptor. They also uncovered how some much larger compounds only target MT1 despite the structural similarities between the two receptors.
Credit: Greg Stewart/SLAC National Accelerator Laboratory


A new study explains the inefficacy of some diabetes drugs

Synchrotron light has been used for the first time to simulate damages due to oxidative stress on the aldose reductase protein with the aim of obtaining its activated form.

This form of the protein, related with some several diabetic complications, is insensitive to the drugs being developed, which hinders the treatment. ALBA researchers have shown that chemical changes suffered by the protein under oxidative stress are the cause of drugs inefficacy in the attempt to block aldose reductase. The team of the Synchrotron suggests a new method for drugs design considering the changes in proteins under oxidative stress, like the ones involved in diseases such as cancer, Parkinson or Alzheimer.
The protein aldose reductase has been explored as a drug target since the 1980s for its implication in diabetic complications. Now, the team of the ALBA Synchrotron, in collaboration with the Autonomous University of Barcelona, has shown the reason why some drugs against the effects of diabetes under development do not work in the attempt to block aldose reductase.
This protein has mainly detoxifying functions inside the cell but it can also transform glucose into a molecule called sorbitol. Under hyperglycemic conditions (high level of glucose in blood), this reaction increases much more and sorbitol accumulates, consuming antioxidant defenses. So, if hyperglycemia situation becomes chronic – like in diabetes -, there are unbalanced conditions inside the cell that lead to harmful oxidative stress environment.

Image: Isidro Crespo, Judith Juanhuix and Albert Castellví, at the biolaboratoy of the ALBA Synchrotron.

Absorber captures excess chemotherapy drugs

The work opens up a new route to fighting cancer that minimizes drug toxicity and enables personalized, targeted, high-dose chemotherapy.

Most anticancer drugs are poisonous, so doctors walk a delicate line when administering chemotherapy. A dose must be sufficient to kill or stop the growth of cancer cells in the target organ, but not high enough to irreparably damage a patient’s other organs. To avoid this, doctors can thread catheters through the bloodstream to deliver chemotherapy drugs directly to the site of the tumor—a method known as intra-arterial chemotherapy. Still, typically more than half of the dose injected into the body escapes the target organ. Several years ago, researchers began working on a major improvement: placing a device “downstream” of the targeted organ to filter out excess chemo so that much less of the drug reaches the body as a whole.

>Read more on the Advanced Light Source

Image: (extract, see here the full image)
(a) Diagram of the proposed approach for drug capture using a 3D-printed cylindrical absorber. (b) Chemical structure of doxorubicin, the chemotherapy drug used in this study. (c) Schematic of the endovascular treatment of liver cancer. Excess drug molecules are captured by the absorber in the vein draining the organ. An introducer sheath guides the absorber to the desired location via a guide wire.

Clear view of “Robo” neuronal receptor opens door for new cancer drugs

During brain development, billions of neuron nerve cells must find accurate pathways in the brain in order to form trillions of neuronal circuits enabling us to enjoy cognitive, sensory and emotional wellbeing.

To achieve this remarkable precision, migrating neurons use special protein receptors that sense the environment around them and guide the way so these neurons stay on the right path. In a new study published in Cell, researchers from Bar-Ilan University and Tel Aviv University in Israel, EMBL Grenoble in France and University of Exeter in the UK report on their discovery of the intricate molecular mechanism that allows a key guidance receptor, “Robo”, to react to signals in its environment.

One of the most important protein signaling systems that guide neurons consists of the cell surface receptor “Robo” and its external guidance cue, “Slit”. “Slit and Robo can be identified in virtually all animals with a nervous system, from a 1 mm-long nematode all the way to humans,” explains researcher Yarden Opatowsky, associate professor and head of the Laboratory of Structural Biology at Bar-Ilan University and who led the research.

>Read more on the European Synchrotron website

Image: A surface representation of the crystal structure of the extracellular portion of human Robo2. The yellow region represents the domain where dimerisation takes place. Here, we see it blocked by the other domains, meaning dimerisation cannot take place and that Robo2 is inactivated.
Credit: Y. Opatowsky.

Structural basis of neurosteroid anesthetic action on GABAA receptors

Type A γ-aminobutyric acid receptors (GABAARs) control neuronal excitability1. They are targets for the treatment of neurological diseases and disorders and also for general anesthetics. The underlying mechanisms of these drugs’ action on GABAARs remain to be determined.
One of the mechanisms is to potentiate function of GABAARs via binding to the transmembrane domain (TMD)2. Ample experimental evidence suggests that the TMD of GABAARs harbors sites for the primary actions of general anesthetics and neurosteroids. The TMD plays an essential role in functional transitions among the resting, activated, and desensitized states of these Cl-conducting channels.
Alphaxalone (5α-pregnan-3α-ol-11,20 dione) is a potent neurosteroid anesthetic. The anxiolytic, anticonvulsant, analgesic, and sedative-hypnotic effects of alphaxalone have been linked to its potentiation of GABA-evoked currents and direct activation of GABAARs3. However, the data about the alphaxalone binding site in GABAARs and the underlying structural basis of alphaxalone’s action are sparse.

>Read more on the Stanford Synchrotron Radiation Lightsource at SLAC

Figure: Alphaxalone-induced structural changes at the bottom of the TMD (a) Bottom view of overlaid TM1-TM2 structures of the apo (orange) and alphaxalone-bound (cyan) α1GABAAR chimera. (b) Side view of overlaid structures of apo (principal subunit – gold; complementary subunit – orange) and alphaxalone-bound (principal subunit – blue; complementary subunit – cyan) α1GABAAR chimera. For clarity, only TM2 and TM3 are shown in the principal subunit and only TM1 and TM2 are shown in the complementary subunit. The arrow highlights structural perturbations originating from the alphaxalone binding site near W246 through the TM1-TM2 linker to the pore-lining residues P253 (-2′) and V257 (2′). (c) The 2FO-FC electron density maps (blue mesh, contoured at 1 σ) covering TM1-TM2 in the apo (left) and alphaxalone-bound (right) α1GABAAR chimera. The sidechains are shown only for residues W246 to V257 (2′).

Encapsulation of drugs for new cancer treatments

Research develops hydrogel from silk protein with potential application in photodynamic therapy

Cancer is a set of diseases characterized by uncontrolled multiplication of cells. One of the main methods for treating this disease is chemotherapy, which uses drugs to block the growth of those cells or to destroy them. In this way, most drugs used interfere with mitosis, the cellular mechanism by which new cells are produced. Therefore, both cancerous and healthy cells are affected, leading to several side effects.
Worldwide, considerable effort has been directed at developing new methods that act directly on the target of treatment. This is the case of so-called photodynamic therapy (PDT), a minimally invasive therapeutic procedure that selectively acts on malignant cells.
The procedure involves the administration of a light-sensitive substance, called a photosensitizing agent. When irradiated at specific wavelengths, the photosensitizer releases oxygen in reactive chemical forms that promote the death of malignant cells, infectious agents and the removal of burns.

>Read more on the Brazilian Synchrotron Light Laboratory (LNLS) website

Revealing the path of a metallodrug in a breast cancer cell

Some types of cancer cannot be treated with classical chemotherapy. Scientists from Inserm, CNRS, Sorbonne University, PSL university, University Grenoble Alpes and ESRF, the European Synchrotron, are working on a metallorganic molecule as an antitumor drug. Their research has given thorough insights into its mechanism in attacking cancer cells. This study is published in Angewandte Chemie.

Triple-negative breast cancer, which represents 10-20% of breast cancers, is not fuelled by hormones. In fact, it tests negative for estrogen and progesterone receptors and excess HER2 protein. This means that it does not respond to hormonal therapy and antibody medicines. Given that it is more aggressive and often has a higher grade than other types of breast cancer, the scientific community is relentlessly trying to find a treatment.

>Read more on the ESRF website

Image: X-ray fluorescence maps of potassium, an essential physiological element of the cell (K, in pink), and, osmium a constitutive element of the metallocifen (Os, in green), in hormone-independent breast cancer cells exposed to the osmocenyl-tamoxifen derivatives.
Credit: Sylvain Bohic.

Toward a blueprint for anti-influenza drugs

The structures provide an atomic-level blueprint from which to design more effective anti-influenza drugs that can overcome growing drug resistance.

Influenza virus infection is a perennial problem. According to the Centers for Disease Control and Prevention, the 2017-18 flu season saw high levels of emergency-department visits for influenza-like illness, high influenza-related hospitalization rates, and elevated and geographically widespread influenza activity for an extended period.

Although yearly vaccinations can reduce the number of flu infections, these vaccines are able to target only a subset of viral strains—there is, as yet, no “universal vaccine.” As a result, there is still a need for antiviral drugs to treat the illness after infection has occurred. This is especially important for groups of people who can experience serious complications from the flu, such as those with respiratory diseases or immune disorders. In recent years, however, resistance to certain classes of antiviral drugs has become a problem.

>Read more on the Advanced Light Source website

Image: Molecular dynamics simulation of a drug molecule, amantadine (cyan sticks), in the M2 proton channel. The drug’s ammonium group (blue tip) mimics hydronium, stabilizing the drug molecule in a position to block the channel.

New cryo-EM Collaboration

UK set to be global leader in providing large-scale industrial access to Cryo-EM for drug discovery thanks to new collaboration.


Thermo Fisher Scientific and Diamond Light Source are creating a step change for life sciences sector, a one-stop shop for structural biology and one of largest cryo-EM sites in the world.
An agreement to launch a new cryo-EM capability for use in the life sciences industry sector by Thermo Fisher Scientific, one of the world leaders in high-end scientific instrumentation, and Diamond Light Source, the UK’s national synchrotron and one of the most advanced scientific facilities in the world, was announced today ahead of the official opening of the new national electron bio-imaging centre (eBIC) which will be held at Diamond on September 12th 2018.

This announcement confirms Diamond as one of the major global cryo-EM sites embedded with an abundance of complementary synchrotron-based techniques, and thereby, provides the life sciences sector with an offer not available anywhere else in the world.

Professor Dave Stuart, Life Sciences Director at Diamond and MRC Professor of Structural Biology at the University of Oxford, Department of Clinical Medicine, says, “Access to 21st century scientific tools to push the boundaries of scientific research is essential for both academia and industry, and what we have created here at Diamond is truly unique in the world in terms of size and scale. The new centre offers the opportunity for almost real-time physiology, capturing proteins in action at cryo-temperatures by flash-freezing them at various stages. What Diamond has created with eBIC is an integrated facility for structural biology, which will accelerate R&D for both industry and academic users. The additional advanced instruments made available by Thermo Fisher will position the UK as a global leader in providing large-scale industrial access to cryo-EM for drug discovery research. Our new collaboration provides a step change in our offer for industry users and helps ensure that R&D remains in the UK.”

>Read more on the Diamond Light Source website

Image: Close up sample loading Krios I.

A new approach for finding Alzheimer’s treatments

Considering what little progress has been made finding drugs to treat Alzheimer’s disease, Maikel Rheinstädter decided to come at the problem from a totally different angle—perhaps the solution lay not with the peptide clusters known as senile plaques typically found in the brains of Alzheimer’s patients, but with the surrounding brain tissue that allowed those plaques to form in the first place.
It was a novel approach that paid off for Rheinstädter and his team of researchers from McMaster University who used the Canadian Light Source in Saskatoon as part of a study of the effect various compounds have on membranes in brain tissue and the possible impact on plaque formation.

“Alzheimer’s disease has interested me for a long time,” said Rheinstädter, a professor in the Department of Physics and Astronomy and the Origins Institute at McMaster. “It is something almost every Canadian will be affected by in their lives.”

>Read more on the Canadian Light Source website

Image: Adam Hitchcock, Adree Khondker and Maikel Rheinstädter.

Just like lego – studying flexible protein for drug delivery

Researchers from the Sapienza University of Rome and its spin-off company MoLiRom (Italy) are spending the weekend at the ESRF to study a protein that could potentially transport anticancer drugs.

Ferritin is a large spherical protein (20 times bigger than haemoglobin) that stores iron within its cavity in every organism. Just like a lego playset, Ferritin assembles and disassembles. It is also naturally targeted to cancer cells. These are the reasons why Ferritin is a great candidate as a drug-transport protein to fight cancer. An international team of scientists from “Sapienza” University of Rome and the SME MoLiRom (Italy) came to the ESRF to explore a special kind of ferritin that shows promising properties. “This is an archaebacterial ferritin that have transformed into a humanised ferritin to try to tackle cancer cells”, explains Matilde Trabuco, a scientist at the Italian SME MoLiRom.

The mechanism looks simple enough: “Ferritin has a natural attraction to cancer cells. If we encapsulate anti-cancer drugs inside it, it will act as a Trojan horse to go inside cells, then it will open up and deliver the drug”.

Ferritins have been widely used as scaffolds for drug-delivery and diagnostics due to their characteristic cage-like structure. Most ferritins are stable and disassemble only by a harsh pH jump that greatly limits the type of possible cargo. The humanised ferritin was engineered to combine assembly at milder conditions with specific targeting of human cancer cells.

 

>Read more on the European Synchrotron Website