Simple sugars connect in long, branched structures to create glycans. Credit: Stock image.
We’re in the middle of National Chemistry Week , which this year focuses on “The Sweet Side of Chemistry—Candy.” Studying sugar chemistry is also relevant to our health.
The sugar in chocolate, taffy and other confections is a type of simple sugar called sucrose. In our bodies, sugars can exist in many forms, ranging from individual units like glucose to long, branched chains known as glycans containing thousands of individual sugar units linked together.
Glycans are involved in just about every aspect of how our cells work. They help make sure proteins are folded into the proper shape so they function correctly. They act as ZIP codes that direct newly made proteins to the right cellular locations. Some divert white blood cells to infection sites, and others serve as anchors for viruses to latch onto.
Because of the diverse and critical roles that glycans play in our bodies, chemists want to learn more about these molecules, with a long-term goal of harnessing them to treat or prevent disease. Read about some of their discoveries in the Why Sugars Might Surprise You article from Inside Life Science and the Life is Sweet article from Findings magazine. The You Are What You Eat chapter from ChemHealthWeb offers more details about the chemistry of sugar.
Meet mitochondria: cellular compartments, or organelles, that are best known as the powerhouses that convert energy from the food we eat into energy that runs a range of biological processes.
As you can see in this close-up of mitochondria from a rat’s heart muscle cell, the organelles have an inner membrane that folds in many places (and that appears here as striations). This folding vastly increases the surface area for energy production. Nearly all our cells have mitochondria, but cells with higher energy demands have more. For instance, a skin cell has just a few hundred, while the cell pictured here has about 5,000.
Scientists are discovering there’s more to mitochondria than meets the eye, especially when it comes to understanding and treating disease.
Read more about mitochondria in this Inside Life Science article.
Structural model of the Cascade surveillance machine. Credit: Ryan Jackson, Montana State University. Click for larger image
To dismantle the viruses that infect them, bacteria have evolved an immune system that identifies invading viral DNA and signals for its destruction. This gene-editing system is called CRISPR, and it’s being harnessed as a tool for modifying human genes associated with disease.
Taking another important step toward this potential application, researchers now know the structure of a key CRISPR component: a multi-subunit surveillance machine called Cascade that identifies the viral DNA. Shaped like a sea horse, Cascade is composed of 11 proteins and CRISPR-related RNA. A research team led by Blake Wiedenheft of Montana State University used X-ray crystallography and computational analysis to determine Cascade’s configuration. In a complementary study, Scott Bailey of Johns Hopkins University and his colleagues determined the structure of the complex bound to a viral DNA target.
Like blueprints, these structural models help scientists understand how Cascade assembles into an efficient surveillance machine and, more broadly, how the CRISPR system functions and how to adapt it as a tool for basic and clinical research.
Montana State University News Release
Johns Hopkins University News Release
A molecule targets the intermediary structure of a protein involved in disease-associated amyloid fibrils. Credit: University of Washington.
Alzheimer’s disease, type 2 diabetes and many other illnesses are linked to the buildup of proteins whose structures have changed into shapes that enable the formation of cell-entangling threads called amyloid fibrils. About 10 years ago, researchers led by Valerie Daggett of the University of Washington used computer simulations to suggest that such proteins, on their way to creating fibrils, form an intermediary structure called an alpha sheet that’s even more toxic to cells than fibrils. Now Daggett’s team has experimentally investigated this possibility. The scientists made alpha sheet molecules expected to bind to amyloid-forming proteins in the computationally predicted intermediate state. When they tested the molecules on two amyloid disease-related proteins, they observed a substantial reduction in fibril formation. The work is still very preliminary, but it highlights a potential new avenue for treating a range of amyloid-related diseases.
This work also was funded by NIH’s National Institute of Allergy and Infectious Diseases.
University of Washington News Release
Monster Mash: Protein Folding Gone Wrong Article from Inside Life Science
Whether it’s a microscope, computer program or lab technique, technology is at the heart of biomedical research. Credit: Stock image.
Whether it’s a microscope, computer program or lab technique, technology is at the heart of biomedical research. Its central role is particularly clear from this month’s posts.
Some show how different tools led to basic discoveries with important health applications. For instance, a supercomputer unlocked the secrets of a drug-making enzyme, a software tool identified disease-causing variations among family members and high-powered microscopy revealed a mechanism allowing microtubules—and a cancer drug that targets them—to work.
Another theme featured in several posts is novel uses for established technologies. The scientists behind the cool image put a new spin on a long-standing imaging technology to gain surprising insights into how some brain cells dispose of old parts. Similarly, the finding related to sepsis demonstrates yet another application of a standard lab technique called polymerase chain reaction: assessing the immune state of people with this serious medical condition.
“We need tools to answer questions,” says NIGMS’ Doug Sheeley, who oversees biomedical technology research resource grants. “When we find the answers, we ask new questions that then require new or improved tools. It’s a virtuous cycle that keeps science moving forward.”
A new software tool analyzes disease-causing genetic variations within a family. Credit: NIH’s National Human Genome Research Institute.
Changes in your DNA sequence occur randomly and rarely. But when they do happen, they can increase your risk of developing common, complex diseases, such as cancer. One way to identify disease-causing variations is to study the genomes of family members, since the changes typically are passed down to subsequent generations.
To rake through a family tree for genetic variations with the highest probabilities of causing a disease, researchers combined several commonly-used statistical methods into a new software tool called pVAAST. The scientific team, which included Mark Yandell and Lynn Jorde of the University of Utah and Chad Huff of the University of Texas MD Anderson Cancer Center, used the tool to identify the genetic causes of a chronic intestinal inflammation disease and of developmental defects affecting the heart, face and limbs.
The results confirmed previously identified genetic variations for the developmental diseases and pinpointed a previously unknown variation for the intestinal inflammation. Together, the findings confirm the ability of the tool to detect disease-causing genetic changes within a family. Another research team has already used the software tool to discover rare genetic changes associated with family cases of breast cancer. These studies are likely just the beginning for studying genetic patterns of diseases than run in a family.
This work also was funded by NIH’s National Institute of Diabetes and Digestive and Kidney Diseases; National Cancer Institute; National Human Genome Research Institute; National Heart, Lung, and Blood Institute; and National Institute of Mental Health.
University of Utah News Release
Yandell , Jorde and Huff Labs
A new compound (chemical structure shown here) blocks the activity of an enzyme involved in glucose regulation.
The discovery of a compound that slows the natural degradation of insulin in mice opens up a new area of investigation in the search for drugs to treat diabetes. The research team, which included David Liu and Alan Saghatelian of Harvard University, Markus Seeliger of Stony Brook University School of Medicine, and Wei-Jen Tang of the University of Chicago focused on insulin-degrading enzyme, or IDE. Using a method called DNA-templated synthesis, the scientists made 14,000 small molecules and found one that bound to the enzyme, suggesting it might modulate the enzyme’s activity. Work in test tubes and in animal models confirmed this—and showed that blocking IDE activity improved insulin levels and glucose tolerance. The researchers also learned that the enzyme is misnamed: In addition to insulin, it degrades two other hormones involved in glucose regulation.
NIGMS’ Peter Preusch says, “This is a very interesting fusion of chemical methods and biology that has uncovered new basic science findings about insulin processing with potential clinical impact.”
This work also was funded by NIH’s National Cancer Institute and the Office of the Director.
Harvard University News Article
Chemistry of Health Booklet
An artistic interpretation of the human proteome. Credit: Corinne Sandone and Jennifer Fairman, Johns Hopkins University.
Genes control the most basic functions of the cell, including what proteins to make and when. In 2003, the Human Genome Project created a draft map of our genes, and now researchers have completed a draft map of the human proteome—the set of all our proteins. The map, which includes proteins encoded by more than 17,000 genes as well as ones from regions of the genome previously thought to be non-coding, will help advance a broad range of research into human health and disease.
Read more about the proteome map in this NIH Research Matters article.
Artist’s rendition of a network diagram. Credit: Allison Kudla, Institute for Systems Biology.
Networks—both real and virtual—are everywhere, from our social media circles to the power grid that delivers electricity. The interactions of genes, proteins and other molecules in a cell are examples of networks, too.
Scientists working in a field called systems biology study and chart living networks to learn how the individual parts work together to make a functioning whole and what happens when these complex, dynamic systems go awry. For example, the network diagram here depicts yeast cells (superimposed circles) and the biochemical “chatter” between them (lines) that tells the cells to gather together in clumps. This clumping helps them survive stressful conditions like a shortage of nutrients.
Network diagrams provide more than just hub-and-spoke pictures. They can yield information that helps us better understand—and potentially influence—complex phenomena that affect our health.
Read more about network analysis and systems biology in this Inside Life Science article.
When proteins enter the proteasome, they’re chopped into bits for re-use. Credit: Office of Biological and Environmental Research of the U.S. Department of Energy Office of Science.
As people around the world mark Earth Day (April 22) with activities that protect the planet, our cells are busy safeguarding their own environment.
To keep themselves neat, tidy and above all healthy, cells rely on a variety of recycling and trash removal systems. If it weren’t for these systems, cells could look like microscopic junkyards—and worse, they might not function properly. Scientists funded by the National Institutes of Health are therefore working to understand the cell’s janitorial services to find ways to combat malfunctions.
Read more about how cells take out the trash and handle recycling in this Inside Life Science article.