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The initial symptoms of whooping cough tend to be mild and resemble a common cold. However, after a week or two, the symptoms worsen into severe and prolonged coughing attacks. The disease is more severe in unvaccinated infants and toddlers. In older children and adults, the disease may be milder with a persistent cough of varying severity. In recent years, despite increases in vaccination, there has been a puzzling resurgence of whooping cough cases in developed countries such as the UK and US. For instance, in 2014, California recorded a peak in reported cases. It is thought that the waning effectiveness of the vaccine may be a major culprit. However, recent studies suggest that the newer vaccines protect against serious disease but may fail to prevent transmission. As such, vaccinated people carrying the bacteria may be transmitting the disease unknowingly to unvaccinated individuals. The pertussis toxin pictured here (PDB: 1PTO) is an important toxin produced by Bordetella pertussis. Antibodies generated against pertussis toxin can be used for treating high-risk infants who are exposed to whooping cough.

Most people are familiar with DNA and RNA as the molecules which store and transmit genetic information in our cells - but did you know that RNA actually serves several other functions? For example, one of the most important molecular machines in any living thing is the ribosome (pictured PDB 4V5D). This molecule is responsible for building proteins by reading messenger RNA (mRNA) and combining amino acids. It turns out, though, that the ribosome largely consists of RNA itself! Two long ribosomal RNA (rRNA) strands - which wrap around themselves to form a complicated three-dimensional structure - associate with each other and several proteins to form this extremely important organelle. This render also shows another interesting form of RNA called transfer RNA (tRNA), in red. This type of RNA carries amino acids to the ribosome. If the tRNA’s recognition sequence, or “anti-codon” matches up to the codon on the mRNA that is being read, the ribosome will incorporate its cargo into the new protein strand. Between mRNA, rRNA, and tRNA, some form of RNA mediates nearly every aspect of the synthesis of the proteins that keep us alive!

Spaghetti! At least that’s what this picture looks like. This “spaghetti” molecule is actually collagen (PDB ID: 1BKV) – a vital part of the human body. The entire human protein content is 30% collagen and our largest organ, skin, is 70% collagen. Its secondary structure is a triple-helix of amino acid fibrils – similar to rope. This makes it perfect to use in situations where large tensile strength is needed. Thus, collagen is also found in the connective tissues of the body such as tendons, ligaments, cartilage, and bones. Collagen is no one-trick pony! There are 29 versions of collagen all with unique functions and purposes. There are many beauty products that contain collagen and maybe you’re skeptical of their claims, but rest assured – there is science behind it! This paper reports that consuming collagen will reduce skin wrinkles and improve overall dermal skin health.

The way we see the world around us would be much different without #rhodopsin. Our retina contains rod cells that utilize rhodopsin to enable us to see things more clearly in dimly lit environments. Inactivated rhodopsin consists of two key components: the trans-membrane protein opsin and its covalently bound partner: a small ligand known as 11-cis-retinal. When rhodopsin absorbs a photon, the ligand isomerizes into its trans conformation and disassociates from opsin, leading to additional structural changes in opsin that begins the signaling cascade. Opsin works as a G protein-coupled receptor (GPCR), recruiting G proteins that convert the signal to electrical impulses. These travel to the brain to be interpreted as vision. Pictured here is bovine rhodopsin (PDB: 1F88), the first GPCR to be determined via x-ray crystallography.

Mistletoe is a plant recognized during the holiday season due to ancient Druidic and Norse traditions that were adopted by the English. It is a common name for a specific hemi-parasitic plant found on the British Isles, but we use it to refer to any parasitic plants with similar habits. Mistletoe plants are toxic if eaten because they contain the active substance alkaloid tyramine (pictured in yellow here, PDB: 5FF9). Symptoms include blurred vision, nausea, abdominal pain, blood pressure changes, and possibly death. However, the plant has been used medicinally in Europe for hundreds of years to treat arthritis, epilepsy, high blood pressure, and infertility. Studies have found it may reduce the side effects of radiation and chemotherapy during cancer treatment.

As the new year approaches, we prepare to exit 2018 and move onto 2019. What better way to exit this year in MOTW than by looking at exosomes. Exosomes are cell-derived vesicles that have recently been positively correlated with ovarian cancer invasiveness – sparking new interest in early detection of ovarian cancer (which has been one of the deadliest types of cancer due to the lack of early detection). Thus, exosomes are being explored for their role as potential biomarkers for general health and disease. One of the accepted markers for exosomes is CD81 (shown here, PDB 5TCX). It is a tetraspanin transmembrane protein with both the N and C terminus being exposed in the intracellular side of the cellular membrane. Using immunoelectron microscopy, researchers have identified tetraspanins as being abundant on a wide variety of endocytic membranes, including exosomes. CD81 contains the best characterized extracellular loop that tetraspanins are known to possess. To learn more about interesting molecules and about our molecular modeling capabilities follow us @macromoltek

Now that winter has finally come ‘round here to Texas, many of us find ourselves shivering when we step outside. However, there's an important part of the population that don't have enough muscle tissue to shiver: infants. Babies have proportionately large heads with high surface area, lack hair, and have developing nervous systems. This makes them particularly susceptible to hypothermia. Fortunately, nearly 5% of their body mass comes from Brown Adipose Tissue, or “brown fat”. Brown fat features mitochondria with Uncoupling Protein 1 (UCP1*), a "proton leak" channel protein. Rather than storing energy in chemical bonds for the rest of the cell to use, the mitochondria in brown fat cells "leak" high energy protons which, in turn, warm up the rest of the body. In addition to human infants, brown adipose tissue is abundant in mammals that hibernate through the winter.

Recent advances in T-cell-based immunotherapies have created very promising first-line and alternative treatments for cancer patients. The most popular treatments include anti-CTLA4 and anti-PD1 therapies that promote the T-cell-mediated killing of specific types of cancer cells. New sets of combinational therapies are developed to potentiate these properties of antibodies. One of them is inhibition of the molecular chaperone HSP90, which facilitates cancer cell survival by stabilizing key proteins that support this malignancy. Here we show a co-crystal structure of HSP90 and its small molecule inhibitor in green (PDB ID: 2QG0).

Orange is the color of autumn. The leaves of the forest change from their deep, summer green to a bright orange, pumpkins adorn neighborhood porches, and our Thanksgiving tables are topped with sweet potato casserole and pumpkin pie. What’s making everything orange you may ask. Well, there’s a nifty little family of proteins responsible called carotenoids. Carotenoids (picture here, PDB: 5UI2) perform the vital task of protecting plants from harmful light-induced damage, so they’re always lurking below the surface. However, the intense green of chlorophyll drowns out the carotenoid-orange hues. The longer nights of autumn signals plants to stop production of chlorophyll. Once this molecule begins to break down, the carotenoids present themselves and paint the forest.