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Intrinsically disordered proteins dynamically sample a wide conformational space and therefore do not adopt a stable and defined three-dimensional conformation. The structural heterogeneity is related to their proper functioning in physiological processes. Knowledge of the conformational ensemble is crucial for a complete comprehension of this kind of proteins. We here present an approach that utilizes dynamic nuclear polarization-enhanced solid-state NMR spectroscopy of sparsely isotope-labeled proteins in frozen solution to take snapshots of the complete structural ensembles by exploiting the inhomogeneously broadened line-shapes. We investigated the intrinsically disordered protein α-synuclein (α-syn), which plays a key role in the etiology of Parkinson's disease, in three different physiologically relevant states. For the free monomer in frozen solution we could see that the so-called "random coil conformation" consists of α-helical and β-sheet-like conformations, and that secondary chemical shifts of neighboring amino acids tend to be correlated, indicative of frequent formation of secondary structure elements. Based on these results, we could estimate the number of disordered regions in fibrillar α-syn as well as in α-syn bound to membranes in different protein-to-lipid ratios. Our approach thus provides quantitative information on the propensity to sample transient secondary structures in different functional states. Molecular dynamics simulations rationalize the results., (Copyright © 2018 Biophysical Society. Published by Elsevier Inc. All rights reserved.)

Amyloid deposits formed from islet amyloid polypeptide (IAPP) are a hallmark of type 2 diabetes mellitus and are known to be cytotoxic to pancreatic β-cells. The molecular structure of the fibrillar form of IAPP is subject of intense research, and to date, different models exist. We present results of solid-state NMR experiments on fibrils of recombinantly expressed and uniformly 13C, 15N-labeled human IAPP in the non-amidated, free acid form. Complete sequential resonance assignments and resulting constraints on secondary structure are shown. A single set of chemical shifts is found for most residues, which is indicative of a high degree of homogeneity. The core region comprises three to four β-sheets. We find that the central 23-FGAILS-28 segment, which is of critical importance for amyloid formation, is part of the core region and forms a β-strand in our sample preparation. The eight N-terminal amino acid residues of IAPP, forming a ring-like structure due to a disulfide bridge between residues C2 and C7, appear to be well defined but with an increased degree of flexibility. This study supports the elucidation of the structural basis of IAPP amyloid formation and highlights the extent of amyloid fibril polymorphism., Competing Interests: The authors have declared that no competing interests exist.

Forschungszentrum Karlsruhe has developed a concept for the utilization of cereal straw and other thin-walled biomass with high ash content. The concept consists of a regional step (drying, chopping, flash-pyrolysis, and mixing) and a central one (pressurized entrained-flow gasification, gas cleaning, synthesis of fuel, and production of byproducts). The purpose of the regional plant is to prepare the biomass by minimizing its volume and producing a stable and safe storage and transport form. In the central gasifier, the pyrolysis products are converted into syngas. The syngas is tar-free and can be used for Fischer-Tropsch synthesis after gas cleaning.

The stability of red blood cell antigens and plasma coagulation factors stored in new plastic blood packs containing either citrate-phosphate-dextrose (CPD) or citrate-phosphate-dextrose-adenine (CPDA-2) was studied. The containers were made of either polyolefin (PL 732TM) plastic without a plasticizer, or polyvinyl chloride with a non-diethylhexyl phthalate (non-DEHP) plasticizer (PL 1240). All studies were done in parallel using standard polyvinyl chloride (PL 146) bags containing DEPH plasticizer as controls. Red blood cell antigen scoring was performed for the A, B, c, D, K, Fya, Lea, Jka, M, and P antigens using cells obtained from both the blood container and tubing segments. Units of fresh frozen plasma and cryoprecipitate were prepared, and age and donor-matched sets of each of these blood components were stored in both test and control plastic containers. The red blood cell antigens showed no decrease in reactivity over 21 (CPD) or 35 (CPDA-2) days of storage in either test plastic compared with controls. For fresh frozen plasma (factors V, VIII, IX) and cryoprecipitate (factor VIII) the factor activity found for the test plastics ranged from 94 to 115 percent of that recorded for the age and donor-matched control plastic. The concentration of fibronectin found in cryoprecipitate stored in the test plastics averaged 90 to 99 percent of the activity found in PL 146 plastic. We conclude that the red blood cell antigens and coagulation factors tested remain stable in the plastic-anticoagulant combinations studied.

Detailed field data on the occurrence, flow pattern, and internal dynamics of both surge and continuous turbidity currents have been obtained with a three-dimensional array of optical and thermal sensors. The array, operated in a glacial lake in southeastern British Columbia, collected detailed information on the character of surge events with velocities reaching 110 centimeters per second and continuous underflows exceeding 90 centimeters per second. Thefindings (i) indicate that such currents are frequent events, occurring with density differences between the incoming stream water and the lake water as low as 0.19 kilogram per cubic meter of water; (ii) document the differences in the initiation and internal characteristics of the continuous and surge events; and (iii) support the concept of erosion by turbidity currents.

Blood was drawn from ten healthy volunteer donors into citrate-phosphate-dextrose adenine (CPDA-1) anticoagulant and placed on the quarantine shelf of the blood bank refrigerator. Plasma glucose, sodium, potassium, chloride, bicarbonate, glutamic-oxaloacetic transaminase, lactate dehydrogenase (LDH) and hemoglobin as well as white cell count, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin concentration, whole blood pH, lactate and ammonia were measured on all samples initially and at one, seven, 14, 21, 28, and 35 days of storage at 4 degrees C. Whole blood lactate was analyzed serially on five of the units. The most pronounced changes were seen for glucose, potassium, bicarbonate, lactate, LDH, ammonia, and hemoglobin. Plasma glucose and bicarbonate declined in concentration while potassium, lactate, LDH, ammonia, and hemoglobin rose with storage. As expected, these changes differed little from those found with steroid blood collected in acid-citrate-dextrose or citrate-phosphate-dextrose.