Atomic-level structure characterization of an ultrafast folding mini-protein denatured state

Atomic-level analyses of non-native protein ensembles constitute an important aspect of protein folding studies to reach a more complete understanding of how proteins attain their native form exhibiting biological activity. Previously, formation of hydrophobic clusters in the 6 M urea-denatured state of an ultrafast folding mini-protein known as TC5b from both photo-CIDNP NOE transfer studies and FCS measurements was observed. Here, we elucidate the structural properties of this mini-protein denatured in 6 M urea performing 15N NMR relaxation studies together with a thorough NOE analysis. Even though our results demonstrate that no elements of secondary structure persist in the denatured state, the heterogeneous distribution of R2 rate constants together with observing pronounced heteronuclear NOEs along the peptide backbone reveals specific regions of urea-denatured TC5b exhibiting a high degree of structural rigidity more frequently observed for native proteins. The data are complemented with studies on two TC5b point mutants to verify the importance of hydrophobic interactions for fast folding. Our results corroborate earlier findings of a hydrophobic cluster present in urea-denatured TC5b comprising both native and non-native contacts underscoring their importance for ultra rapid folding. The data assist in finding ways of interpreting the effects of pre-existing native and/or non-native interactions on the ultrafast folding of proteins; a fact, which might have to be considered when defining the starting conditions for molecular dynamics simulation studies of protein folding

Mechanical thrombectomy in acute stroke – Five years of experience in Poland

Objectives Mechanical thrombectomy (MT) is not reimbursed by the Polish public health system. We present a description of 5 years of experience with MT in acute stroke in Comprehensive Stroke Centers (CSCs) in Poland. Methods and results We retrospectively analyzed the results of a structured questionnaire from 23 out of 25 identified CSCs and 22 data sets that include 61 clinical, radiological and outcome measures. Results Most of the CSCs (74%) were founded at University Hospitals and most (65.2%) work round the clock. In 78.3% of them, the working teams are composed of neurologists and neuro-radiologists. All CSCs perform CT and angio-CT before MT. In total 586 patients were subjected to MT and data from 531 of them were analyzed. Mean time laps from stroke onset to groin puncture was 250±99min. 90.3% of the studied patients had MT within 6h from stroke onset; 59.3% of them were treated with IV rt-PA prior to MT; 15.1% had IA rt-PA during MT and 4.7% – emergent stenting of a large vessel. M1 of MCA was occluded in 47.8% of cases. The Solitaire device was used in 53% of cases. Successful recanalization (TICI2b–TICI3) was achieved in 64.6% of cases and 53.4% of patients did not experience hemorrhagic transformation. Clinical improvement on discharge was noticed in 53.7% of cases, futile recanalization – in 30.7%, mRS of 0–2 – in 31.4% and mRS of 6 in 22% of cases. Conclusion Our results can help harmonize standards for MT in Poland according to international guidelines

Cryoconite – from minerals and organic matter to bioengineeredsediments on glacier's surfaces

Cryoconite is a mixture of mineral and organic material covering glacial ice, playing important roles in biogeochemical cycles and lowering the albedo of a glacier surface. Understanding the differences in structure of cryoconite across the globe can be important in recognizing past and future changes in supraglacial environments and ice-organisms-minerals interactions. Despite the worldwide distribution and over a century of studies, the basic characteristics of cryoconite, including its forms and geochemistry, remain poorly studied. The major purpose of our study is the presentation and description of morphological diversity, chemical and photoautotrophs composition, and organic matter content of cryoconite sampled from 33 polar and mountain glaciers around the globe. Observations revealed that cryoconite is represented by various morphologies including loose and granular forms. Granular cryoconite includes smooth, rounded, or irregularly shaped forms; with some having their surfaces covered by cyanobacteria filaments. The occurrence of granules increased with the organic matter content in cryoconite.Moreover, amajor driver of cryoconite colouringwas the concentration of organicmatter and its interplay with minerals. The structure of cyanobacteria and algae communities in cryoconite differs between glaciers, but representatives of cyanobacteria families Pseudanabaenaceae and Phormidiaceae, and algae families Mesotaeniaceae and Ulotrichaceaewere themost common. Themost of detected cyanobacterial taxa are known to produce polymeric substances (EPS) that may cement granules. Organic matter content in cryoconite varied between glaciers, ranging from 1% to 38%. The geochemistry of all the investigated samples reflected local sediment sources, except of highly concentrated Pb andHg in cryoconite collected fromEuropean glaciers near industrialized regions, corroborating cryoconite as element-specific collector and potential environmental indicator of anthropogenic activity. Our work supports a notion that cryoconite may bemore than just simple sediment and instead exhibits complex structure with relevance for biodiversity and the functioning of glacial ecosystem

Zastosowanie Alteplazy w oknie terapeutycznym udaru mózgu w przebiegu kardiomiopatii

Stroke is a threat to the health and life of the patient. Only early diagnosis and treatment in the so-called therapeutic window, enable effective help. This case represents an untreated 65-year-old man who suffered an acute stroke and was in a severe condition with full aphasia and hemiparesis transmitted by a medical emergency team in the emergency room of a hospital with a peripheral unit. Reliable intelligence at the scene, rapid transport to a dedicated treatment center, early imaging diagnostics and implemented thrombolytic therapy within 4.5 hours after the onset of symptoms, allowed to obtain a satisfactory final effect, despite co-existing cardiomyopathy.Udar mózgu stanowi zagrożenie zdrowia i życia pacjenta. Tylko wczesne rozpoznanie, diagnostyka i leczenie w tzw. oknie terapeutycznym, umożliwiają skuteczną pomoc. Omawiany przypadek przedstawia nieleczonego 65.letniego mężczyznę, który doznał ostrego udaru mózgu i w stanie ciężkim z pełną afazją i niedowładem połowiczym został przekazany przez zespół ratownictwa medycznego na izbie przyjęć szpitala dysponującego oddziałem udarowym. Rzetelny wywiad na miejscu zdarzenia, szybki transport do dedykowanego ośrodka leczniczego, wczesna diagnostyka obrazowa i wdrożona terapia trombolityczna w przeciągu 4,5 godziny od wystąpienia objawów, pozwoliły na uzyskanie satysfakcjonującego efektu końcowego, mimo współistniejącej kardiomiopatii

Growth of thin polymer films containing side-chain azo-dye analyzed by atomic force microscopy

International audienceThin films containing both the azo-dye disperse red 1 (DR1) and the poly(methylmetacrylate) (PMMA) or the poly(phenylenevinylene) (PPV) are deposited by Langmuir–Blodgett and spin coating techniques on various substrates. The morphology, surface structure and growth pattern of the azo-dye-polymers were studied by atomic force microscopy. Nucleation and growth processes are responsible for the generation of different structures. The spin coated films were additionally oriented using the electric field poling method (corona poling). The film homogeneity is improved by this method in all cases. Due to the polar character of DR1 molecules, rod-like sub-structures are observed after the corona poling process in DR1–MMA films. The indium tin oxide surface enhances reorientation of the azo-dye-polymer molecules during corona poling and results in a significant reduction of the surface roughness

Average area buried upon folding & helix propensities.

<p>Plot of the average area buried upon folding (AABUF; upper part) and the helix propensities (lower part) for TC5b (black) and its P12W (red) point mutant.</p

NMR-derived native state structure of TC5b (PDB entry: 1L2Y).

<p>Highlighted is the Trp 6 residue (blue) (see text) together with the cage-forming side chains of Tyr 3 (dark blue), Ile 4 (yellow), Leu 7 (light blue), Pro 12 (red), Arg 16 (green), Pro 18 (brown), and Pro 19 (pink).</p

Reduced spectral density functions.

<p>(<b>A</b>) , (<b>B</b>) and (<b>C</b>) for 6 M urea-denatured TC5b derived from the 60.25 MHz <i>R</i>₁, <i>R</i>₂, and heteronuclear NOE relaxation data from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041301#pone-0041301-g003" target="_blank">Figure 3</a>. The average errors are 2.5%, 1.2% and 2.7%, for , and , respectively.</p