For thousands of years, Chinese herbalists have treated malaria using Chang Shan, a root extract from a type of hydrangea that grows in Tibet and Nepal. Recent studies have suggested Chang Shan can also reduce scar formation, treat multiple sclerosis and even slow cancer progression.

A 360-degree view of the molecule himastatin, which was first isolated from the bacterium Streptomyces himastatinicus. Himastatin shows antibiotic activity. The researchers who created this video developed a new, more concise way to synthesize himastatin so it can be studied more easily.

More information about the research that produced this video can be found in the Science paper “Total synthesis of himastatin” by D’Angelo et al.

Related to images 6848 and 6850.

Cdc42, a member of the Rho family of small guanosine triphosphatase (GTPase) proteins, regulates multiple cell functions, including motility, proliferation, apoptosis, and cell morphology. In order to fulfill these diverse roles, the timing and location of Cdc42 activation must be tightly controlled. Klaus Hahn and his research group use special dyes designed to report protein conformational changes and interactions, here in living neutrophil cells. Warmer colors in this image indicate higher levels of activation. Cdc42 looks to be activated at cell protrusions.

Related to images 2452, 2453, and 2454.

A cross section of the measles virus in which six proteins work together to infect cells. The measles virus is extremely infectious; 9 out of 10 people exposed will contract the disease. Fortunately, an effective vaccine protects against infection.

For a zoomed-in look at the six important proteins, see Measles Virus Proteins.

A crystal of RNase A protein created for X-ray crystallography, which can reveal detailed, three-dimensional protein structures.

The illustration shows the capsid of human immunodeficiency virus (HIV) whose molecular features were resolved with cryo-electron microscopy (cryo-EM). On the left, the HIV capsid is "naked," a state in which it would be easily detected by and removed from cells. However, as shown on the right, when the viral capsid binds to and is covered with a host protein, called cyclophilin A (shown in red), it evades detection and enters and invades the human cell to use it to establish an infection. To learn more about how cyclophilin A helps HIV infect cells and how scientists used cryo-EM to find out the mechanism by which the HIV capsid attaches to cyclophilin A, see this news release by the University of Illinois. A study reporting these findings was published in the journal Nature Communications.

CellPack image of the H1N1 influenza virus, with hemagglutinin and neuraminidase glycoproteins in green and red, respectively, on the outer envelope (white); matrix protein in gray, and ribonucleoprotein particles inside the virus in red and green. Related to image 6356.

The receptor is shown bound to a partial inverse agonist, carazolol.

Solution NMR structure of protein target WR41 (left) from C. elegans. Noting the unanticipated structural similarity to the ubiquitin protein (Ub) found in all eukaryotic cells, researchers discovered that WR41 is a Ub-like modifier, ubiquitin-fold modifier 1 (Ufm1), on a newly uncovered ubiquitin-like pathway. Subsequently, the PSI group also determined the three-dimensional structure of protein target HR41 (right) from humans, the E2 ligase for Ufm1, using both NMR and X-ray crystallography.

The G switch allows our bodies to respond rapidly to hormones. G proteins act like relay batons to pass messages from circulating hormones into cells. A hormone (red) encounters a receptor (blue) in the membrane of a cell. Next, a G protein (green) becomes activated and makes contact with the receptor to which the hormone is attached. Finally, the G protein passes the hormone's message to the cell by switching on a cell enzyme (purple) that triggers a response. See image 2536 and 2537 for other versions of this image. Featured in Medicines By Design.

Researchers have created artificial cilia that wave like the real thing. Zvonimir Dogic and his Brandeis University colleagues combined just a few cilia proteins to create cilia that are able to wave and sweep material around--although more slowly and simply than real ones. The researchers are using the lab-made cilia to study how the structures coordinate their movements and what happens when they don't move properly. Featured in the August 18, 2011, issue of Biomedical Beat.

Model of the catalytic portion of an enzyme, receptor-type tyrosine-protein phosphatase from humans. The enzyme consists of two identical protein subunits, shown in blue and green. The groups made up of purple and red balls represent phosphate groups, chemical groups that can influence enzyme activity. This phosphatase removes phosphate groups from the enzyme tyrosine kinase, counteracting its effects.

This image shows the structure of a synapse, or junction between two nerve cells in three dimensions. From the brain of a mouse.

The three fibers of the cytoskeleton--microtubules in blue, intermediate filaments in red, and actin in green--play countless roles in the cell.

A protein called tubulin (green) accumulates in the center of a nucleus (outlined in pink) from an aging cell. Normally, this protein is kept out of the nucleus with the help of gatekeepers known as nuclear pore complexes. But NIGMS-funded researchers found that wear and tear to long-lived components of the complexes eventually lowers the gatekeepers' guard. As a result, cytoplasmic proteins like tubulin gain entry to the nucleus while proteins normally confined to the nucleus seep out. The work suggests that finding ways to stop the leakage could slow the cellular aging process and possibly lead to new therapies for age-related diseases.

A rendering of an activity biosensor image overlaid with a cell-centered frame of reference used for image analysis of signal transduction. This is an example of NIH-supported research on single-cell analysis. Related to 2798 , 2799, 2800, 2801 and 2803.

The chemical structure of the morphine molecule

This illustration highlights spherical pre-synaptic vesicles that carry the neurotransmitter glutamate. The presynaptic and postsynaptic membranes are shown with proteins relevant for transmitting and modulating the neuronal signal.

PDB 101’s Opioids and Pain Signaling video explains how glutamatergic synapses are involved in the process of pain signaling.

This 2-hour-old fly embryo already has a blueprint for its formation, and the process for following it is so precise that the difference of just a few key molecules can change the plans. Here, blue marks a high concentration of Bicoid, a key signaling protein that directs the formation of the fly's head. It also regulates another important protein, Hunchback (green), that further maps the head and thorax structures and partitions the embryo in half (red is DNA). The yellow dots overlaying the embryo plot the concentration of Bicoid versus Hunchback proteins within each nucleus. The image illustrates the precision with which an embryo interprets and locates its halfway boundary, approaching limits set by simple physical principles. This image was a finalist in the 2008 Drosophila Image Award.

Under the microscope, an E. coli cell lights up like a fireball. Each bright dot marks a surface protein that tells the bacteria to move toward or away from nearby food and toxins. Using a new imaging technique, researchers can map the proteins one at a time and combine them into a single image. This lets them study patterns within and among protein clusters in bacterial cells, which don't have nuclei or organelles like plant and animal cells. Seeing how the proteins arrange themselves should help researchers better understand how cell signaling works.

The 3D single-molecule super-resolution reconstruction of the entire nuclear lamina in a HeLa cell was acquired using the TILT3D platform. TILT3D combines a tilted light sheet with point-spread function (PSF) engineering to provide a flexible imaging platform for 3D single-molecule super-resolution imaging in mammalian cells.
See 6573 for 3 separate views of this structure.

Gene transcription is a process by which information encoded in DNA is transcribed into RNA. It's essential for all life and requires the activity of proteins, called transcription factors, that detect where in a DNA strand transcription should start. In eukaryotes (i.e., those that have a nucleus and mitochondria), a protein complex comprising 14 different proteins is responsible for sniffing out transcription start sites and starting the process. This complex represents the core machinery to which an enzyme, named RNA polymerase, can bind to and read the DNA and transcribe it to RNA. Scientists have used cryo-electron microscopy (cryo-EM) to visualize the TFIID-RNA polymerase-DNA complex in unprecedented detail. This animation shows the different TFIID components as they contact DNA and recruit the RNA polymerase for gene transcription.

To learn more about the research that has shed new light on gene transcription, see this news release from Berkeley Lab.

Related to image 3766.

HIV is a retrovirus, a type of virus that carries its genetic material not as DNA but as RNA. Long before anyone had heard of HIV, researchers in labs all over the world studied retroviruses, tracing out their life cycle and identifying the key proteins the viruses use to infect cells. When HIV was identified as a retrovirus, these studies gave AIDS researchers an immediate jump-start. The previously identified viral proteins became initial drug targets. See images 2513 and 2515 for other versions of this illustration. Featured in The Structures of Life.

RNA incorporated into the CRISPR surveillance complex is positioned to scan across foreign DNA. Cryo-EM density from a 3Å reconstruction is shown as a yellow mesh.

From PDB entry 3c6k, Crystal structure of human spermine synthase in complex with spermidine and 5-methylthioadenosine.

This short video shows a model of the DNA helicase in yeast. This DNA helicase has 11 proteins that work together to unwind DNA during the process of copying it, called DNA replication. Scientists used a technique called cryo-electron microscopy (cryo-EM), which allowed them to study the helicase structure in solution rather than in static crystals. Cryo-EM in combination with computer modeling therefore allows researchers to see movements and other dynamic changes in the protein. The cryo-EM approach revealed the helicase structure at much greater resolution than could be obtained before. The researchers think that a repeated motion within the protein as shown in the video helps it move along the DNA strand. To read more about DNA helicase and this proposed mechanism, see this news release by Brookhaven National Laboratory.

Some children are born with a mutation in a regulatory site on this enzyme that causes them to over-secrete insulin when they consume protein. We found that a compound from green tea (shown in the stick figure and by the yellow spheres on the enzyme) is able to block this hyperactivity when given to animals with this disorder.

Molecular model of the struture of heme. Heme is a small, flat molecule with an iron ion (dark red) at its center. Heme is an essential component of hemoglobin, the protein in blood that carries oxygen throughout our bodies. This image first appeared in the September 2013 issue of Findings Magazine. View side view of heme here 3540.

This painting shows a cross section of a small respiratory droplet, like the ones that are thought to transmit SARS-CoV-2, the virus that causes COVID-19. The virus is shown in pink, and the droplet is also filled with molecules that are present in the respiratory tract, including mucins (green), pulmonary surfactant proteins and lipids (blue), and antibodies (tan).

This image shows a computer-generated, three-dimensional map of the rotavirus structure. This virus infects humans and other animals and causes severe diarrhea in infants and young children. By the age of five, almost every child in the world has been infected with this virus at least once. Scientists have found a vaccine against rotavirus, so in the United States there are very few fatalities, but in developing countries and in places where the vaccine is unavailable, this virus is responsible for more than 200,000 deaths each year.

The rotavirus comprises three layers: the outer, middle and inner layers. On infection, the outer layer is removed, leaving behind a "double-layered particle." Researchers have studied the structure of this double-layered particle with a transmission electron microscope. Many images of the virus at a magnification of ~50,000x were acquired, and computational analysis was used to combine the individual particle images into a three-dimensional reconstruction.

The image was rendered by Melody Campbell (PhD student at TSRI). Work that led to the 3D map was published in Campbell et al. Movies of ice-embedded particles enhance resolution in electron cryo-microscopy. Structure. 2012;20(11):1823-8. PMCID: PMC3510009.

This image was part of the Life: Magnified exhibit that ran from June 3, 2014, to January 21, 2015, at Dulles International Airport.

A global "map of the protein structure universe" indicating the positions of specific proteins. The preponderance of small, less-structured proteins near the origin, with the more highly structured, large proteins towards the ends of the axes, may suggest the evolution of protein structures.

Force vectors computed from actin cytoskeleton flow. This is an example of NIH-supported research on single-cell analysis. Related to 2798, 2800, 2801, 2802 and 2803.

Cdc42, a member of the Rho family of small guanosine triphosphatase (GTPase) proteins, regulates multiple cell functions, including motility, proliferation, apoptosis, and cell morphology. In order to fulfill these diverse roles, the timing and location of Cdc42 activation must be tightly controlled. Klaus Hahn and his research group use special dyes designed to report protein conformational changes and interactions, here in living neutrophil cells. Warmer colors in this image indicate higher levels of activation. Cdc42 looks to be activated at cell protrusions.

Related to images 2451, 2452, and 2453.

2.5Å resolution reconstruction of rabbit muscle aldolase collected on a FEI/Thermo Fisher Titan Krios with energy filter and image corrector.

This is a fibroblast, a connective tissue cell that plays an important role in wound healing. Normal fibroblasts have smooth edges. In contrast, this spiky cell is missing a protein that is necessary for proper construction of the cell's skeleton. Its jagged shape makes it impossible for the cell to move normally. In addition to compromising wound healing, abnormal cell movement can lead to birth defects, faulty immune function, and other health problems.

This image was part of the Life: Magnified exhibit that ran from June 3, 2014, to January 21, 2015, at Dulles International Airport.

Cell showing overproduction of the ARTS protein (red). ARTS triggers apoptosis, as shown by the activation of caspase-3 (green) a key tool in the cell's destruction. The nucleus is shown in blue. Image is featured in October 2015 Biomedical Beat blog post Cool Images: A Halloween-Inspired Cell Collection.

Model of a member from the Tex protein family, which is implicated in transcriptional regulation and highly conserved in eukaryotes and prokaryotes. The structure shows significant homology to a human transcription elongation factor that may regulate multiple steps in mRNA synthesis.

Proteins are 3D structures made up of smaller units. DNA is transcribed to RNA, which in turn is translated into amino acids. Amino acids form a protein strand, which has sections of corkscrew-like coils, called alpha helices, and other sections that fold flat, called beta sheets. The protein then goes through complex folding to produce the 3D structure.

The lubber grasshopper, found throughout the southern United States, is frequently used in biology classes to teach students about the respiratory system of insects. Unlike mammals, which have red blood cells that carry oxygen throughout the body, insects have breathing tubes that carry air through their exoskeleton directly to where it's needed. This image shows the breathing tubes embedded in the weblike sheath cells that cover developing egg chambers.

This image was part of the Life: Magnified exhibit that ran from June 3, 2014, to January 21, 2015, at Dulles International Airport.

Network diagram showing a map of protein-protein interactions in a yeast (Saccharomyces cerevisiae) cell. This cluster includes 78 percent of the proteins in the yeast proteome. The color of a node represents the phenotypic effect of removing the corresponding protein (red, lethal; green, nonlethal; orange, slow growth; yellow, unknown).

Developing spermatids (precursors of mature sperm cells) begin as small, round cells and mature into long-tailed, tadpole-shaped ones. In the sperm cell's head is the cell nucleus; in its tail is the power to outswim thousands of competitors to fertilize an egg. As seen in this microscopy image, fruit fly spermatids start out as groups of interconnected cells. A small lipid molecule called PIP2 helps spermatids tell their heads from their tails. Here, PIP2 (red) marks the nuclei and a cell skeleton-building protein called tubulin (green) marks the tails. When PIP2 levels are too low, some spermatids get mixed up and grow with their heads at the wrong end. Because sperm development is similar across species, studies in fruit flies could help researchers understand male infertility in humans.

This video shows the structure of the pore-forming protein VDAC-1 from humans. This molecule mediates the flow of products needed for metabolism--in particular the export of ATP--across the outer membrane of mitochondria, the power plants for eukaryotic cells. VDAC-1 is involved in metabolism and the self-destruction of cells--two biological processes central to health.

Related to videos 2570 and 2572.

The G switch allows our bodies to respond rapidly to hormones. G proteins act like relay batons to pass messages from circulating hormones into cells. A hormone (red) encounters a receptor (blue) in the membrane of a cell. Next, a G protein (green) becomes activated and makes contact with the receptor to which the hormone is attached. Finally, the G protein passes the hormone's message to the cell by switching on a cell enzyme (purple) that triggers a response. See image 2536 and 2538 for other versions of this image. Featured in Medicines By Design.

This ribbon drawing of a protein hand drawn and colored by researcher Jane Richardson in 1981 helped originate the ribbon representation of proteins that is now ubiquitous in molecular graphics. The drawing shows the 3-dimensional structure of the protein triose phosphate isomerase. The green arrows represent the barrel of eight beta strands in this structure and the brown spirals show the protein's eight alpha helices. A black and white version of this drawing originally illustrated a review article in Advances in Protein Chemistry, volume 34, titled "Anatomy and Taxonomy of Protein Structures." The illustration was selected as Picture of The Day on the English Wikipedia for November 19, 2009. Other important and beautiful images of protein structures by Jane Richardson are available in her Wikimedia gallery.

Related to image 6355.

Ribosomes are complex machines made up of more than 50 proteins and three or four strands of genetic material called ribosomal RNA (rRNA). The busy cellular machines make proteins, which are critical to almost every structure and function in the cell. To do so, they read protein-building instructions, which come as strands of messenger RNA. Ribosomes are found in all forms of cellular life—people, plants, animals, even bacteria. This illustration of a bacterial ribosome was produced using detailed information about the position of every atom in the complex. Several antibiotic medicines work by disrupting bacterial ribosomes but leaving human ribosomes alone. Scientists are carefully comparing human and bacterial ribosomes to spot differences between the two. Structures that are present only in the bacterial version could serve as targets for new antibiotic medications.

Relapsing fever is caused by a bacterium and transmitted by certain soft-bodied ticks or body lice. The disease is seldom fatal in humans, but it can be very serious and prolonged. This scanning electron micrograph shows Borrelia hermsii (green), one of the bacterial species that causes the disease, interacting with red blood cells. Micrograph by Robert Fischer, NIAID. Related to image 3586.
For more information about relapsing fever, see https://www.cdc.gov/relapsing-fever/index.html.
This image is part of the Life: Magnified collection, which was displayed in the Gateway Gallery at Washington Dulles International Airport June 3, 2014, to January 21, 2015.

CCD-1 is an enzyme produced by the bacterium Clostridioides difficile that helps it resist antibiotics. Using X-ray crystallography, researchers determined the structure of a CCD-1 molecule and a molecule of the antibiotic cefotaxime bound together. The structure revealed that CCD-1 provides extensive hydrogen bonding and stabilization of the antibiotic in the active site, leading to efficient degradation of the antibiotic.

Related to images 6764, 6765, and 6767.

The receptor is shown bound to a small molecule peptide called CVX15.

This eerily glowing blob isn't an alien or a creature from the deep sea--it's a mouse embryo just eight and a half days old. The green shell and core show a protein called Smad4. In the center, Smad4 is telling certain cells to begin forming the mouse's liver and pancreas. Researchers identified a trio of signaling pathways that help switch on Smad4-making genes, starting immature cells on the path to becoming organs. The research could help biologists learn how to grow human liver and pancreas tissue for research, drug testing and regenerative medicine. In addition to NIGMS, NIH's National Institute of Diabetes and Digestive and Kidney Diseases also supported this work.