Category: Molecular Structures

Science Snippet: The Power of Proteins

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Some might think that protein is only important for weightlifters. In truth, all life relies on the activity of protein molecules. A single human cell contains thousands of different proteins with diverse roles, including:

A dense network of blue, green, yellow, and red weblike structures along a border of a cell.
Actin proteins in a cell’s cytoskeleton. Credit: Xiaowei Zhuang, HHMI, Harvard University, and Nature Publishing Group.
  • Providing structure. Proteins such as actin make up the three-dimensional cytoskeleton that gives cells structure and determines their shapes.
  • Aiding chemical reactions. Many proteins are biological catalysts called enzymes that speed up the rate of chemical reactions by reducing the amount of energy needed for the reactions to proceed. For example, lactase is an enzyme that breaks down lactose, a sugar found in dairy products. Those with lactose intolerance don’t produce enough lactase to digest dairy.
  • Supporting communication. Some proteins act as chemical messengers between cells. For example, cytokines are the protein messengers of the immune system and can increase or decrease the intensity of an immune response.
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Manganese: The Magical Element?

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The element manganese is essential for human life. It’s aptly named after the Greek word for magic, and some mysteries surrounding its role in the body still exist today—like how our bodies absorb it, if very high or low levels can cause illness, or how it might play a role in certain diseases.

A graphic showing manganese’s symbol Mn, atomic number 25, and atomic weight 54.938 connected by lines to illustrations of steel railways, a bone, and a drinking can. Manganese steel contains ~13 percent manganese. It’s very strong and used for railways, safes, and prison bars. Manganese is essential for organisms. It’s needed for strong bones, and many enzymes also contain it. Drink cans are made with an alloy of aluminum and manganese, which helps prevent corrosion. Across the bottom of the graphic are the logo for the Royal Society of Chemistry celebrating IYPT 2019, the Compound Interest logo, and #IYPT2019. Manganese is necessary for metabolism, bone formation, antioxidation, and many other important functions in the body. The element is found in strong steel, bones and enzymes, and drink cans. Credit: Compound Interest CC BY-NC-ND 4.0. Click to enlarge.
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Slideshow: Circles of Life

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Every year on March 14, many people eat pie in honor of Pi Day. Mathematically speaking, pi (π) is the ratio of a circle’s circumference (the distance around the outside) to its diameter (the length from one side of the circle to the other, straight through the center). That means if you divide the circumference of any circle by its diameter, the solution will always be pi, which is roughly 3.14—hence March 14, or 3/14. But pi is an irrational number, which means that the numbers after the decimal point never end. With the help of computers, mathematicians have determined trillions of digits of pi.

To celebrate Pi Day, check out this slideshow of circular microbes, research organisms, and laboratory tools (while you enjoy your pie, of course!). To explore more scientific photos, videos, and illustrations, visit our image and video gallery.

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Got Calcium?

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Someone’s hand moving to scroll through this blog post is possible because of a mineral that both gives bones their strength and allows muscles to move: calcium. As the most abundant mineral in our bodies, it’s essential for lots of important functions. It’s found in many foods, medicines, and dietary supplements.

A graphic showing calcium’s symbol “Ca”, atomic number, and atomic weight connected by lines to illustrations of teeth and bones, cheese, and a cement-mixing truck (calcium carbonate is used in construction). Calcium keeps your bones strong, allows your muscles to move, and is important for many other bodily functions. The element is found in foods, medicines, and the world around us. Credit: Compound Interest CC BY-NC-ND 4.0. Click to enlarge.
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So Much to Do, So Little Selenium Needed

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You may know that antioxidants can help protect your cells from oxidative damage, but do you know about selenium—an element often found in special proteins called antioxidant enzymes? Selenium is essential to your body, which means you must get it from the food you eat. But it’s a trace element so you only need a small amount to benefit from its effects. In addition to its antioxidant properties, it’s also important for reproduction, DNA synthesis, and hormone metabolism.

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Science Snippet: ATP’s Amazing Power

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A twisted, blue crystalline structure with a small yellow molecule inside it.
ATP (yellow) powering a protein (blue) that moves material within cells and helps them divide. Credit: Charles Sindelar, Yale University.

Just as electricity powers almost every modern gadget, the tiny molecule adenosine triphosphate (ATP) is the major source of energy for organisms’ biochemical reactions. ATP stores energy in the chemical bonds that hold its three phosphate groups together—the triphosphate part of its name. In the human body, ATP powers processes such as cell signaling, muscle contraction, nerve firing, and DNA and RNA synthesis. Because our cells are constantly using and producing ATP, each of us turns over roughly our body weight in the molecule every day!

Our bodies can produce ATP in several ways, but the most common is cellular respiration—a multistep process in which glucose molecules from our diet and oxygen react to form water and carbon dioxide. The breakdown of a single molecule of glucose in this way releases energy, which the body captures and stores in around 32 ATP molecules. Along with oxygen, mitochondria are crucial for producing ATP through cellular respiration, which is why they’re sometimes called the powerhouses of cells.

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State of the Art: New Crystallography Equipment Aids Science and the Study of Artifacts

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Upgrading X-ray crystallography equipment at the University of Arkansas in Fayetteville has had an unexpected benefit: enabling analyses that could help art museums authenticate, restore, and learn more about their pieces.

Intertwined curled ribbons.
Two copies of a protein (pink and purple) produced by the hepatitis C virus interacting with the same strand of DNA (green). This structure was solved using equipment at the University of Arkansas X-ray crystallography center. Credit: PDB 2F55.

Scientists use X-ray crystallography to determine the detailed 3D structures of molecules. In biomedical contexts, researchers often apply X-ray crystallography to map the structures of proteins and other biomolecules like DNA and RNA. A molecule’s structure can shed light on its function and help answer scientific questions. For example, knowing the structures of proteins involved in antibiotic resistance can help researchers determine how those molecules work and how to combat bacteria that produce them.

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Fifty Years of the Protein Data Bank!

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Macromolecular structures in the shape of the number 50. Protein Data Bank’s 50 years logo. Credit: PDB website.

The Protein Data Bank (PDB), established in 1971, is the single global repository for 3D structural data of proteins, DNA, RNA, and even complexes these biological molecules form with drugs or other small molecules. More than 1 million people—including researchers, medical professionals, educators, and students—use the PDB each year. NIGMS and other parts of NIH have helped fund this free digital resource since 1978.

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More Than 25 Years of Competition and Collaboration Advance the Prediction of Protein Shapes

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Proteins (such as hemoglobin, actin, and amylase) are workhorse molecules that contribute to virtually every activity in the body. Some of proteins’ many jobs include carrying oxygen from your lungs to the rest of your body (hemoglobin), allowing your muscles to move (actin and myosin), and digesting your food (amylase, pepsin, and lactase). All proteins are made up of chains of amino acids that fold into specific 3D structures, and each protein’s structure allows it to perform its distinct job. Proteins that are misfolded or misshapen can cause diseases such as Parkinson’s or cataracts.

While it’s straightforward to use the genetic code to predict amino acid sequences of proteins from gene sequences, the vast diversity of protein shapes and many factors that influence a protein’s 3D structure make it much more complicated to create simple folding rules that could be used to predict proteins’ structures from these sequences. Scientists have worked on this problem for nearly 50 years, and NIGMS has supported many of their efforts, including the Critical Assessment of Structure Prediction (CASP) program.

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