Comparing the Folding and Misfolding Energy Landscapes of Phosphoglycerate Kinase

AbstractPartitioning of polypeptides between protein folding and amyloid formation is of outstanding pathophysiological importance. Using yeast phosphoglycerate kinase as model, here we identify the features of the energy landscape that decide the fate of the protein: folding or amyloidogenesis. Structure formation was initiated from the acid-unfolded state, and monitored by fluorescence from 10 ms to 20 days. Solvent conditions were gradually shifted between folding and amyloidogenesis, and the properties of the energy landscape governing structure formation were reconstructed. A gradual transition of the energy landscape between folding and amyloid formation was observed. In the early steps of both folding and misfolding, the protein searches through a hierarchically structured energy landscape to form a molten globule in a few seconds. Depending on the conditions, this intermediate either folds to the native state in a few minutes, or forms amyloid fibers in several days. As conditions are changed from folding to misfolding, the barrier separating the molten globule and native states increases, although the barrier to the amyloid does not change. In the meantime, the native state also becomes more unstable and the amyloid more stable. We conclude that the lower region of the energy landscape determines the final protein structure

A macroeconomics-inspired interpretation of the terrestrial water cycle

This article develops an approach that applies macroeconomic concepts to the interpretation of complex, water related natural processes. By translating and reinterpreting these processes into a language that is more accessible to a broader audience otherwise unaccustomed to its terms will likely help sharpen our understanding of the terrestrial water cycle. For economists, we describe climate-forming natural processes in a manner consistent with the fundamentals of the mainstream approach. For noneconomists, parallels from economically determined, relatively short-term observations can be applied conceptually to identify dynamics which occur over much longer and therefore more elusive natural occurrences, in particular considering the role of forests and how persistent land conversion over a millennium has shaped the earth's surface and impacted climate stability. The set of “supporting ecosystem services” highlighted in the Millennium Ecosystem Assessment (MEA) coincides with the ground phase of the terrestrial water cycle, taking the concept beyond the ecosystem service perspective and identifying it as a planetary service. Ecosystem and planetary services differ in the same way that microeconomic and macroeconomic perspectives do. The water cycle intensity of a geographical area may well be related to a rainfall multiplier that measures the ability of continental ecosystems to increase the amount of water moving across terrestrial surfaces and descending as rainfall through transpiration and deposition, and re-transpiration and re-deposition of the water content in the air that originally arrives from the oceans. Building upon the MEA's association of human wellbeing with ecosystem features, the rainfall multiplier serves as a physical indicator and measure of the natural basis of wellbeing creation

Cryptocapsinepoxide-type Carotenoids from Red Mamey, Pouteria sapota

Three new carotenoids, cryptocapsin-5,6-epoxide, 3ʹ-deoxycapsanthin-5,6-epoxide, and cryptocapsin-5,8-epoxides, have been isolated from the ripe fruits of red mamey (Pouteria sapota). Cryptocapsin-5,6-epoxide was prepared by partial synthesis via epoxidation of cryptocapsin and the (5R,6S)- and (5S,6R)-stereoisomers were identified by HPLC-ECD analysis. Spectroscopic data of the natural (anti) and semisynthetic (syn) derivatives obtained by acid-catalyzed rearrangement of cryptocapsin-5,8-epoxide stereoisomers were compared for structural elucidation. Chiral HPLC separation of natural and semisynthetic samples of cryptocapsin-5,8-epoxides was performed and HPLC-ECD analysis allowed configurational assignment of the separated stereoisomers

Status of the mid-IR ELT imager and spectrograph (METIS)

The Mid-Infrared ELT Imager and Spectrograph (METIS) is one of three first light instruments on the ELT. It will provide high-contrast imaging and medium resolution, slit-spectroscopy from 3 - 19um, as well as high resolution (R ∼ 100,000) integral field spectroscopy from 2.9-5.3μm. All modes observe at the diffraction limit of the ELT, by means of adaptive optics, yielding angular resolutions of a few tens of milliarcseconds. The range of METIS science is broad, from Solar System objects to active galactic nuclei (AGN). We will present an update on the main science drivers for METIS: circum-stellar disks and exoplanets. The METIS project is now in full steam, approaching its preliminary design review (PDR) in 2018. In this paper we will present the current status of its optical, mechanical and thermal design as well as operational aspects. We will also discuss the challenges of building an instrument for the ELT, and the required technologies. © 2018 SPIE

Mid-infrared circumstellar emission of the long-period Cepheid l Carinae resolved with VLTI/MATISSE

Stars and planetary system

A review of high contrast imaging modes for METIS

The Mid-infrared E-ELT Imager and Spectrograph (METIS) for the European Extremely Large Telescope (E- ELT) consists of diffraction-limited imagers that cover 3 to 14 microns with medium resolution (R ∼ 5000) long slit spectroscopy, and an integral field spectrograph for high spectral resolution spectroscopy (R ∼ 100,000) over the L and M bands. We present our approach for high contrast imaging with METIS, covering diffraction suppression with coronagraphs, the removal of residual aberrations using QACITS1, 2 and Phase Sorting Interferometry (PSI),3 and simulations demonstrating the expected contrast