Search results for "Intrinsic"
showing 10 items of 386 documents
Human Intrinsic Factor Expression for Bioavailable Vitamin B12 Enrichment in Microalgae
2018
Dietary supplements and functional foods are becoming increasingly popular complements to regular diets. A recurring ingredient is the essential cofactor vitamin B12(B12). Microalgae are making their way into the dietary supplement and functional food market but do not produce B12, and their B12 content is very variable. In this study, the suitability of using the human B12-binding protein intrinsic factor (IF) to enrich bioavailable B12 using microalgae was tested. The IF protein was successfully expressed from the nuclear genome of the model microalga Chlamydomonas reinhardtii and the addition of an N-terminal ARS2 signal peptide resulted in efficient IF secretion to the medium. Co-abunda…
FRET-based dynamic structural biology: Challenges, perspectives and an appeal for open-science practices.
2021
International audience; Single-molecule FRET (smFRET) has become a mainstream technique for studying biomolecular structural dynamics. The rapid and wide adoption of smFRET experiments by an ever- increasing number of groups has generated significant progress in sample preparation, measurement procedures, data analysis, algorithms and documentation. Several labs that employ smFRET approaches have joined forces to inform the smFRET community about streamlining how to perform experiments and analyze results for obtaining quantitative information on biomolecular structure and dynamics. The recent efforts include blind tests to assess the accuracy and the precision of smFRET experiments among d…
Structural Basis of the High Affinity Interaction between the Alphavirus Nonstructural Protein-3 (nsP3) and the SH3 Domain of Amphiphysin-2
2016
We show that a peptide from Chikungunya virus nsP3 protein spanning residues 1728–1744 binds the amphiphysin-2 (BIN1) Src homology-3 (SH3) domain with an unusually high affinity (Kd 24 nM). Our NMR solution complex structure together with isothermal titration calorimetry data on several related viral and cellular peptide ligands reveal that this exceptional affinity originates from interactions between multiple basic residues in the target peptide and the extensive negatively charged binding surface of amphiphysin-2 SH3. Remarkably, these arginines show no fixed conformation in the complex structure, indicating that a transient or fluctuating polyelectrostatic interaction accounts for this …
Dispersion from Cα or NH: 4D experiments for backbone resonance assignment of intrinsically disordered proteins
2020
AbstractResonance assignment of intrinsically disordered proteins is remarkably challenging due to scant chemical shift dispersion arising from conformational heterogeneity. The challenge is even greater if repeating segments are present in the amino acid sequence. To forward unambiguous resonance assignment of intrinsically disordered proteins, we present iHACANCO, HACACON and (HACA)CONCAHA, three Hα-detected 4D experiments with Cα as an additional dimension. In addition, we present (HACA)CON(CA)NH and (HACA)N(CA)CONH, new 4D Hα-start, HN-detect experiments which have two NH dimensions to enhance peak dispersion in a sequential walk through C′, NH and HN, and provide more accurate NH/HN ch…
1H, 13C, and 15N NMR chemical shift assignment of the complex formed by the first EPEC EspF repeat and N-WASP GTPase binding domain
2021
AbstractLEE-encoded effector EspF (EspF) is an effector protein part of enteropathogenic Escherichia coli’s (EPEC’s) arsenal for intestinal infection. This intrinsically disordered protein contains three highly conserved repeats which together compose over half of the protein’s complete amino acid sequence. EPEC uses EspF to hijack host proteins in order to promote infection. In the attack EspF is translocated, together with other effector proteins, to host cell via type III secretion system. Inside host EspF stimulates actin polymerization by interacting with Neural Wiskott-Aldrich syndrome protein (N-WASP), a regulator in actin polymerization machinery. It is presumed that EspF acts by di…
Autonomy-Supportive and Controlling Styles of Teaching
2015
Autonomy-supportive and controlling styles of teaching are usually considered to be the opposite ends of a single continuum. An alternative view, however, is that individuals can perceive both styles simultaneously, which suggests that they are different constructs ( Bartholomew, Ntoumanis, Ryan, Bosch, & Thøgersen-Ntoumani, 2011 ). Using cluster analysis, Study 1 (N = 160) confirmed that both teaching styles were perceived by students. Four clusters appeared depending on the student’s score on the measures of autonomy and controlling styles (high autonomy–high control; low autonomy–low control; high autonomy–low control; low autonomy–high control). Participants in the high autonomy–lo…
Synthesis and solution properties of star-shaped poly(tert-butyl acrylate)
2000
A series of star polymers consisting of poly(tert-butyl acrylate) arms and an ethyleneglycol dimethacrylate (EGDMA) microgel core were synthesized using anionic polymerization. The effect of various parameters (precursor length, ratio [[EGDMA]/[Initiator], reaction time, and overall concentrations) on the average number of arms was investigated. Molecular weights were determined using GPC coupled with an online viscometer and MALLS. The exponents for the relation between intrinsic viscosity or radius of gyration and molecular weight, respectively, are extremely low, indicating that the dimensions of the star polymers only slightly increase with the number of arms. After a certain number of …
Adsorptionseffekte als Fehlerquellen bei Lichtzerstreuungsmessungen
1956
Es werden die Einflusse der Adsorption von Hochpolymeren aus den Losungen auf Lichtzerstreuungsmessungen untersucht. Zunachst wird die Adsorption aus Losung an Glaswolle und Glaspulver in verschiedenen Losungsmitteln gemessen. Es zeigt sich, das sowohl Konzentrationserniedrigung, bestimmt im Differentialrefraktometer, wie auch eine Abnahme des Molekulargewichtes, aus der Lichtzerstreuung bestimmt, infolge selektiver Adsorption auftreten. Beim Schutteln der Losungen tritt als weiterer Effekt ein Abbau der Kettenmolekule ein. Beim Filtrieren von Losungen nehmen durch Adsorption im Filter Konzentration und Molekulargewicht ab. Die Abnahme wachst mit der Feinheit des Filters, d. h. mit seiner O…
Outcomes of single versus double hormone receptor–positive breast cancer. A GEICAM/9906 sub-study
2018
Abstract Background Retrospective data suggest better outcomes for patients with double hormonal receptor (oestrogen [ER] and progesterone receptor [PgR])–positive (dHR+) early breast cancer, compared with single hormonal receptor–positive, sHR+, (ER+/PgR– or ER–/PgR+) disease. Here, we evaluate the classification according to intrinsic subtypes and clinical outcomes of sHR+ versus dHR+ in HER2-negative breast cancer patients enrolled in GEICAM/9906 study ( NCT00129922 ). Methods Archival tumours were retrieved retrospectively for the analysis of ER, PgR and HER2 status and classified into intrinsic subtypes using the PAM50 gene expression assay. Disease-free survival (DFS) and overall surv…
Physical activity in adulthood: genes and mortality.
2015
AbstractObservational studies report a strong inverse relationship between leisure-time physical activity and all-cause mortality. Despite suggestive evidence from population-based associations, scientists have not been able to show a beneficial effect of physical activity on the risk of death in controlled intervention studies among individuals who have been healthy at baseline. On the other hand, high cardiorespiratory fitness is known to be a strong predictor of reduced mortality, even more robust than physical activity level itself. Here, in both animals and/or human twins, we show that the same genetic factors influence physical activity levels, cardiorespiratory fitness and risk of de…