Stealthy. Aggressive. Lethal. Assassin flies are predators that hunt and feed on other insects. They are the third most diverse group of flies, with more […]

The post Killer Insect profile: The Assassin Fly appeared first on Smithsonian Insider.

The debate about the world’s oldest tattoos is over—they belong to Ötzi, the European Tyrolean Iceman who died and was buried beneath an Alpine glacier […]

The post Ancient Ink: Iceman Otzi Has World’s Oldest Tattoos appeared first on Smithsonian Insider.

In April 2015, after traveling for about half the age of the universe, a flood of powerful gamma rays from a distant galaxy slammed into […]

The post VERITAS Detects Gamma Rays from Galaxy Halfway Across the Visible Universe appeared first on Smithsonian Insider.

Through sheer coincidence, two Smithsonian researchers at the National Zoological Park have discovered that 18 percent of the white-tailed deer population in the Eastern United […]

The post Smithsonian study reveals white-tailed deer in eastern U.S. are infected with a malaria parasite appeared first on Smithsonian Insider.

Einstein’s general theory of relativity predicts the emission of gravitational waves by massive celestial bodies moving though space-time. For the past century gravitational waves have […]

The post Astronomers complete First Search for Visible Light Associated with Gravitational Waves appeared first on Smithsonian Insider.

Cobia, a promising fish for aquaculture, lives throughout the world’s oceans except in the Central and Eastern Pacific. In August 2015, a large number of […]

The post Invasive Cobia Spreads in Panama appeared first on Smithsonian Insider.

Smothered in tartar sauce and cheese it’s difficult to know just what species of fish lurks beneath the breaded surface of a fast-food fish sandwich. […]

The post Smithsonian scientist creating DNA database to track Caribbean conch and lobster appeared first on Smithsonian Insider.

It is rare but not entirely uncommon to see a manatee swimming in the Atlantic waters of Maryland and Virginia. This one was dead, however, […]

The post In face of mass extinctions, Smithsonian’s Global Genome Initiative quietly saves world’s DNA appeared first on Smithsonian Insider.

The National Zoo’s red panda habitat on Asia Trail reopened to the public Tuesday, May 10. Tusa and Asa explored their new home which has […]

The post Red pandas come back to Zoo appeared first on Smithsonian Insider.

When soil temperatures 8 inches under the ground reach a balmy 64 degrees Fahrenheit, periodical cicadas emerge on the U.S. East Coast. They tend to […]

The post Billions & Billions of Periodical Cicadas appeared first on Smithsonian Insider.

For the first time in more than 15 years zebras will graze the fields at the Smithsonian Conservation Biology Institute in Front Royal, Va. Three […]

The post Rare Zebras graze at Smithsonian appeared first on Smithsonian Insider.

Thirty years after the scimitar-horned oyrx were driven to extinction, the desert antelope will return to the last-known place it existed: Chad’s Sahelian grasslands. The […]

The post Extinct-in-the-Wild Antelope Return to the Grasslands of Chad appeared first on Smithsonian Insider.

The center of the Milky Way galaxy is currently a quiet place where a supermassive black hole slumbers, only occasionally slurping small sips of hydrogen […]

The post The Milky Way’s blowout bash 6 million years ago! appeared first on Smithsonian Insider.

There’s something exciting and strange about having an idea. It can come suddenly. Unexpectedly. Randomly. Intensely. Ideas can uninvitingly appear full-forced and bright—like the cliché […]

The post Making the Smithsonian’s New “Sidedoor” podcast series a reality appeared first on Smithsonian Insider.

In 1935, 101 cane toads from Hawaii were set loose in Australia to help control beetles that were decimating the Australian sugar crop. But instead […]

The post Discovery: Australia’s invasive cane toads modify their bodies to conquer new territory faster appeared first on Smithsonian Insider.

Living in deep reefs in the Atlantic Ocean, the banded basslet, a small and colorful species with a wide range of distribution, has long been […]

The post Fishy Caribbean ‘juveniles’ recognized as new species appeared first on Smithsonian Insider.

A one-cubic-foot approach to studying biodiversity as showcased in the new Biocube exhibit at the Smithsonian’s National Museum of Natural History has led to the […]

The post New parasitic crab species discovered during Smithsonian Biocube work in Solomon Islands appeared first on Smithsonian Insider.

In 1969, 60 to 100 peacock bass imported from Buga, Colombia, were introduced into a pond in Panama for sport fishing. Several individuals escaped. By […]

The post Peacock bass invasion Had devastating, long-term impact on Panama’s Fish appeared first on Smithsonian Insider.

Fat, toxic and nocturnal, cane toads (Rhinella marina) are abundant today in Hawaii, even though they are South American natives. Released on the Hawaiian Islands […]

The post Two invasive species have Hawaiian reunion after 80-year separation appeared first on Smithsonian Insider.

NASA’s InSight probe, scheduled to land on the surface of Mars in November 2018, will be boring. Boring a hole, that is. It will drill […]

The post ISO: a boring Martian landing spot for NASA’s InSight probe appeared first on Smithsonian Insider.

Fast radio bursts (FRBs) are brief spurts of radio emission, lasting just one-thousandth of a second, whose origins are mysterious. Fewer than two dozen have […]

The post Astronomers propose cell phone search for galactic radio bursts appeared first on Smithsonian Insider.

For centuries, cultures around the world have used masks in ritual dances and festivals to represent traditional characters. This copper mask, found in the Smithsonian’s […]

The post Mexican Masks: Tales Through Dance appeared first on Smithsonian Insider.

The search for extraterrestrial intelligence has looked for many different signs of alien life, from radio broadcasts to laser flashes, without success. However, newly published […]

The post Could Fast Radio Bursts Be Powering Alien Probes? appeared first on Smithsonian Insider.

Tool use by sea otters to break open well-armored food is not necessarily a family matter, according to a new study published this week by […]

The post Tool use by sea otters has little to do with genetic ties: Smithsonian study appeared first on Smithsonian Insider.

Whales from both poles migrate long distances to breed in tropical waters. Smithsonian scientist Hector M. Guzman and Fernando Félix at the Salinas Whale Museum […]

The post Whale tagging in Southeast Pacific provides data for species protection appeared first on Smithsonian Insider.

For more than 60 years, researchers have tried to successfully cryopreserve (or freeze) the embryo of zebrafish, a species that is an important medical model […]

The post Gold nanotechnology and lasers used to successfully freeze fish embryos appeared first on Smithsonian Insider.

The world’s most indestructible species, the tardigrade, an eight-legged micro-animal, also known as the water bear, will survive until the Sun dies, according to a […]

The post Study determines microscopic water bears will be Earth’s last survivors appeared first on Smithsonian Insider.

In a new study in which one of humankind’s most high-tech tools was used to analyze one of its most primitive, scientists have uncovered evidence […]

The post Laser beams unveil secrets locked inside primitive stone spear points appeared first on Smithsonian Insider.

Hundreds of experiments have shown biodiversity fosters healthier, more productive ecosystems. But many experts doubted whether these experiments would hold up in the real world. […]

The post In the wild, biodiversity’s power surpasses what experiments predict appeared first on Smithsonian Insider.

When fast radio bursts, or FRBs, were first detected in 2001, astronomers had never seen anything like them before. Since then, astronomers have found a […]

The post New study indicates mysterious fast radio bursts occur in universe every second appeared first on Smithsonian Insider.

Plastic debris floating in the ocean has become a powerful new passport to far-away destinations for a wide variety of invasive species, according to new […]

The post Tsunami reveals drifting ocean plastic opens globe to invasive castaways appeared first on Smithsonian Insider.

This animation shows how binary neutron stars warp space-time to create gravitational waves, then collide and explode into a visible kilonova, which can be detected […]

The post Astronomers see light show associated with gravitational waves appeared first on Smithsonian Insider.

The Giant Magellan Telescope Organization (GMTO) today announced that it has initiated the casting of the fifth of seven mirrors that will form the heart of […]

The post Fifth mirror cast for Giant Magellan Telescope appeared first on Smithsonian Insider.

The next generation of the Sloan Digital Sky Survey (SDSS-V), directed by Juna Kollmeier of the Carnegie Institution for Science, will move forward with mapping […]

The post Next generation astronomical survey to map the entire sky appeared first on Smithsonian Insider.

In 1854, a curious-looking spider was found preserved in 50 million-year-old amber. With an elongated neck-like structure and long mouthparts that protruded from the “head” […]

The post These newly discovered pelican spiders will make you want to visit Madagascar appeared first on Smithsonian Insider.

There are currently more than 3,500 confirmed known exoplanets thanks to the remarkable sensitivity of the Kepler spacecraft and to technological advances in space and […]

The post Astronomers detect comets transiting distant stars appeared first on Smithsonian Insider.

A team of astrophysicists and planetary scientists has predicted that Neptune-like planets located near the center of the Milky Way galaxy have been transformed into […]

The post Black hole blasts may transform “Mini-Neptunes” into rocky worlds appeared first on Smithsonian Insider.

Poaching wasn’t the largest conservation concern for Asian elephants, an endangered species, until satellite tracking stunned researchers. Scientists at the Smithsonian Conservation Biology Institute (SCBI) […]

The post Poachers are killing endangered Asian elephants for their skin and meat, not their tusks appeared first on Smithsonian Insider.

Marine mammologist Matthew Leslie aims his crossbow from the bow of a moving boat at the dolphins riding the breaking waves below. A dolphin will […]

The post Some dolphins cross the Pacific more easily than others. Why that matters for protecting them appeared first on Smithsonian Insider.

When a natural disaster strikes, it devastates lives and homes, and can even destroy a culture’s identity and history. After a disaster, humanitarian response is […]

The post Protecting Puerto Rico’s heritage from another disaster appeared first on Smithsonian Insider.

 Extinct species don’t usually get a do-over… but don’t tell that to the scimitar-horned oryx. Erased from the wild for three decades, these desert […]

The post Podcast: Don’t call me extinct appeared first on Smithsonian Insider.

Ninety Limosa harlequin frogs (Atelopus limosus) bred in human care are braving the elements of the wild after Smithsonian scientists sent them out into the […]

The post Panama: First release of endangered frogs appeared first on Smithsonian Insider.

Smithsonian scientists have joined NASA and other organizations this summer to do something incredible: launch a spacecraft, the Parker Solar Probe, into space and have […]

The post A solar probe is on its way to touch the sun. The Smithsonian built the tool that will measure the sun without melting appeared first on Smithsonian Insider.

l-Hydroxyproline (l-Hyp) is a nonstandard amino acid that is present in certain proteins, in some antibiotics and in the cell-wall components of plants. l-Hyp is the product of the post-translational modification of protein prolines by prolyl hydroxylase enzymes, and the isomers trans-3-hydroxy-l-proline (T3LHyp) and trans-4-hydroxy-l-proline (T4LHyp) are major components of mammalian collagen. T4LHyp follows two distinct degradation pathways in bacteria and mammals, while T3LHyp is metabolized by a two-step metabolic pathway that is conserved in bacteria and mammals, which involves a T3LHyp dehydratase and a Δ1-pyrroline-2-carboxylate (Pyr2C) reductase. In order to shed light on the structure and catalysis of the enzyme involved in the second step of the T3LHyp degradation pathway, the crystal structure of Pyr2C reductase from the archaeon Thermococcus litoralis DSM 5473 complexed with NADH and l-proline is presented. The model allows the mapping of the residues involved in cofactor and product binding and represents a valid model for rationalizing the catalysis of Pyr2C reductases.

Aldo-keto reductases (AKRs) are NADPH/NADP+-dependent oxidoreductase enzymes that metabolize an aldehyde/ketone to the corresponding alcohol. AKR4C14 from rice exhibits a much higher efficiency in metabolizing malondialdehyde (MDA) than do the Arabidopsis enzymes AKR4C8 and AKR4C9, despite sharing greater than 60% amino-acid sequence identity. This study confirms the role of rice AKR4C14 in the detoxification of methylglyoxal and MDA, and demonstrates that the endogenous contents of both aldehydes in transgenic Arabidopsis ectopically expressing AKR4C14 are significantly lower than their levels in the wild type. The apo structure of indica rice AKR4C14 was also determined in the absence of the cofactor, revealing the stabilized open conformation. This is the first crystal structure in AKR subfamily 4C from rice to be observed in the apo form (without bound NADP+). The refined AKR4C14 structure reveals a stabilized open conformation of loop B, suggesting the initial phase prior to cofactor binding. Based on the X-ray crystal structure, the substrate- and cofactor-binding pockets of AKR4C14 are formed by loops A, B, C and β1α1. Moreover, the residues Ser211 and Asn220 on loop B are proposed as the hinge residues that are responsible for conformational alteration while the cofactor binds. The open conformation of loop B is proposed to involve Phe216 pointing out from the cofactor-binding site and the opening of the safety belt. Structural comparison with other AKRs in subfamily 4C emphasizes the role of the substrate-channel wall, consisting of Trp24, Trp115, Tyr206, Phe216, Leu291 and Phe295, in substrate discrimination. In particular, Leu291 could contribute greatly to substrate selectivity, explaining the preference of AKR4C14 for its straight-chain aldehyde substrate.

Pullulanase (EC 3.2.1.41) is a well known starch-debranching enzyme that catalyzes the cleavage of α-1,6-glycosidic linkages in α-glucans such as starch and pullulan. Crystal structures of a type I pullulanase from Paenibacillus barengoltzii (PbPulA) and of PbPulA in complex with maltopentaose (G5), maltohexaose (G6)/α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD) were determined in order to better understand substrate binding to this enzyme. PbPulA belongs to glycoside hydrolase (GH) family 13 subfamily 14 and is composed of three domains (CBM48, A and C). Three carbohydrate-binding sites identified in PbPulA were located in CBM48, near the active site and in domain C, respectively. The binding site in CBM48 was specific for β-CD, while that in domain C has not been reported for other pullulanases. The domain C binding site had higher affinity for α-CD than for G6; a small motif (FGGEH) seemed to be one of the major determinants for carbohydrate binding in this domain. Structure-based mutations of several surface-exposed aromatic residues in CBM48 and domain C had a debilitating effect on the activity of the enzyme. These results suggest that both CBM48 and domain C play a role in binding substrates. The crystal forms described contribute to the understanding of pullulanase domain–carbohydrate interactions.

Death-associated protein kinase 1 (DAPK1) is a serine/threonine protein kinase that regulates apoptosis and autophagy. DAPK1 is considered to be a therapeutic target for amyloid-β deposition, endometrial adenocarcinomas and acute ischemic stroke. Here, the potent inhibitory activity of the natural anthraquinone purpurin against DAPK1 phosphorylation is shown. Thermodynamic analysis revealed that while the binding affinity of purpurin is similar to that of CPR005231, which is a DAPK1 inhibitor with an imidazopyridazine moiety, the binding of purpurin was more enthalpically favorable. In addition, the inhibition potencies were correlated with the enthalpic changes but not with the binding affinities. Crystallographic analysis of the DAPK1–purpurin complex revealed that the formation of a hydrogen-bond network is likely to contribute to the favorable enthalpic changes and that stabilization of the glycine-rich loop may cause less favorable entropic changes. The present findings indicate that purpurin may be a good lead compound for the discovery of inhibitors of DAPK1, and the observation of enthalpic changes could provide important clues for drug development.

Mycoplasma hyopneumoniae is a prokaryotic pathogen that colonizes the respiratory ciliated epithelial cells in swine. Infected animals suffer respiratory lesions, causing major economic losses in the porcine industry. Characterization of the immunodominant membrane-associated proteins from M. hyopneumoniae may be instrumental in the development of new therapeutic approaches. Here, the crystal structure of P46, one of the main surface-antigen proteins, from M. hyopneumoniae is presented and shows N- and C-terminal α/β domains connected by a hinge. The structures solved in this work include a ligand-free open form of P46 (3.1 Å resolution) and two ligand-bound structures of P46 with maltose (2.5 Å resolution) and xylose (3.5 Å resolution) in open and closed conformations, respectively. The ligand-binding site is buried in the cleft between the domains at the hinge region. The two domains of P46 can rotate with respect to each other, giving open or closed alternative conformations. In agreement with this structural information, sequence analyses show similarities to substrate-binding members of the ABC transporter superfamily, with P46 facing the extracellular side as a functional subunit. In the structure with xylose, P46 was also bound to a high-affinity (Kd = 29 nM) Fab fragment from a monoclonal antibody, allowing the characterization of a structural epitope in P46 that exclusively involves residues from the C-terminal domain. The Fab structure in the complex with P46 shows only small conformational rearrangements in the six complementarity-determining regions (CDRs) with respect to the unbound Fab (the structure of which is also determined in this work at 1.95 Å resolution). The structural information that is now available should contribute to a better understanding of sugar nutrient intake by M. hyopneumoniae. This information will also allow the design of protocols and strategies for the generation of new vaccines against this important swine pathogen.

Despite the importance of seasonally dry forests, little is known of their ecology. Now, a new book The Ecology and Conservation of Seasonally Dry Forests in Asia, published by Smithsonian Institution Scholarly Press, explores these unique ecosystems, its animals, plants, and the people that inhabit them.

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