26 research outputs found

    Extreme disorder in an ultrahigh-affinity protein complex

    Full text link
    Molecular communication in biology is mediated by protein interactions. According to the current paradigm, the specificity and affinity required for these interactions are encoded in the precise complementarity of binding interfaces. Even proteins that are disordered under physiological conditions or that contain large unstructured regions commonly interact with well-structured binding sites on other biomolecules. Here we demonstrate the existence of an unexpected interaction mechanism: the two intrinsically disordered human proteins histone H1 and its nuclear chaperone prothymosin-α associate in a complex with picomolar affinity, but fully retain their structural disorder, long-range flexibility and highly dynamic character. On the basis of closely integrated experiments and molecular simulations, we show that the interaction can be explained by the large opposite net charge of the two proteins, without requiring defined binding sites or interactions between specific individual residues. Proteome-wide sequence analysis suggests that this interaction mechanism may be abundant in eukaryotes

    Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018.

    Get PDF
    Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field

    Overweight and Severe Acute Maternal Morbidity in a Low-Risk Pregnant Population in The Netherlands

    Get PDF
    <div><p>Objective</p><p>To investigate the association between overweight and severe acute maternal morbidity (SAMM) in a low-risk pregnant population.</p> <p>Design</p><p>Nationwide case-control study.</p> <p>Setting</p><p>The Netherlands, august 2004 to august 2006.</p> <p>Population</p><p>1567 cases from initially primary care and 2994 women from primary care practices as controls, out of 371 012 women delivering in the Netherlands during the study period</p> <p>Methods</p><p>Cases were women with SAMM obtained from a nationwide prospective study. All women in this cohort who initially had low-risk pregnancies were compared with low-risk women without SAMM to calculate odd ratios (ORs) to develop SAMM by body mass index (BMI) category. We divided body mass index in three overweight categories and calculated the ORs (95% CI) of total SAMM and per specific endpoint by logistic regression, with normal weight as reference. We adjusted for age, parity and socio-economic status.</p> <p>Main Outcome Measures</p><p>SAMM, defined as Intensive Care Unit (ICU)-admission, Uterine Rupture, Eclampsia or Major Obstetric Haemorrhage (MOH)</p> <p>Results</p><p>SAMM was reported in 1567 cases which started as low-risk pregnancies. BMI was available in 1097 (70.0%) cases and 2994 control subjects were included. Analysis showed a dose response relation for overweight (aOR, 1.3; 95% CI, 1.0-1.5), obese (aOR, 1.4; 95% CI, 1.1-1.9) and morbidly obese (aOR, 2.1; 95% CI, 1.3-3.2) women to develop SAMM compared to normal weight. Sub analysis showed the same dose response relation for ICU-admission, Uterine Rupture and Eclampsia. We found no association for MOH.</p> <p>Conclusion</p><p>Overweight without pre-existent co-morbidity is an important risk-indicator for developing SAMM. This risk increases with an increasing body mass index.</p> </div

    Comment on "Innovative scattering analysis shows that hydrophobic disordered proteins are expanded in water"

    Full text link
    Riback (Reports, 13 October 2017, p. 238) used small-angle x-ray scattering (SAXS) experiments to infer a degree of compaction for unfolded proteins in water versus chemical denaturant that is highly consistent with the results from Förster resonance energy transfer (FRET) experiments. There is thus no "contradiction" between the two methods, nor evidence to support their claim that commonly used FRET fluorophores cause protein compaction

    Study characteristics of the included studies summarized for three exposures.

    No full text
    <p>Data are presented as number or range.</p>a<p>Three studies did not report follow-up time.</p>b<p>Two studies did not report the number of participants who encountered the outcome of interest.</p>c<p>One study did not report the number of participants who encountered the outcome of interest.</p><p>HOMA-IR, Homeostasis Model Assessment Insulin Resistance; CHD, coronary heart disease; CVD, cardiovascular disease.</p

    Results of random-effect meta-analyses comparing cardiovascular disease risk for an increase of one standard deviation.

    No full text
    <p><sup>a</sup>1 study did not specify sex-specific numbers. SD, standard deviation; 95% CI, 95% confidence interval; I<sup>2</sup>, measure of heterogeneity; CHD, coronary heart disease and is defined as fatal or non-fatal myocardial infarction or angina pectoris; CVD, cardiovascular disease and is defined as myocardial infarction, angina pectoris, hemorrhagic stroke, ischemic stroke, arrhythmias, congestive heart failure or sudden cardiac death; HOMA-IR, Homeostasis Model Assessment Insulin Resistance.</p

    Summary of search results.

    No full text
    <p><sup>a</sup>One publication consisted of two studies. HOMA-IR, Homeostasis Model Assessment insulin resistance.</p

    Consistent view of polypeptide chain expansion in chemical denaturants from multiple experimental methods

    Full text link
    There has been a long-standing controversy regarding the effect of chemical denaturants on the dimensions of unfolded and intrinsically disordered proteins: A wide range of experimental techniques suggest that polypeptide chains expand with increasing denaturant concentration, but several studies using small-angle X-ray scattering (SAXS) have reported no such increase of the radius of gyration (Rg). This inconsistency challenges our current understanding of the mechanism of chemical denaturants, which are widely employed to investigate protein folding and stability. Here, we use a combination of single-molecule Förster resonance energy transfer (FRET), SAXS, dynamic light scattering (DLS), and two-focus fluorescence correlation spectroscopy (2f-FCS) to characterize the denaturant dependence of the unfolded state of the spectrin domain R17 and the intrinsically disordered protein ACTR in two different denaturants. Standard analysis of the primary data clearly indicates an expansion of the unfolded state with increasing denaturant concentration irrespective of the protein, denaturant, or experimental method used. This is the first case in which SAXS and FRET have yielded even qualitatively consistent results regarding expansion in denaturant when applied to the same proteins. To more directly illustrate this self-consistency, we used both SAXS and FRET data in a Bayesian procedure to refine structural ensembles representative of the observed unfolded state. This analysis demonstrates that both of these experimental probes are compatible with a common ensemble of protein configurations for each denaturant concentration. Furthermore, the resulting ensembles reproduce the trend of increasing hydrodynamic radius with denaturant concentration obtained by 2f-FCS and DLS. We were thus able to reconcile the results from all four experimental techniques quantitatively, to obtain a comprehensive structural picture of denaturant-induced unfolded state expansion, and to identify the most likely sources of earlier discrepancies

    Two cases of Emergomyces pasteurianus infection in immunocompromised patients in the Netherlands

    No full text
    We report two cases of Emergomyces pasteurianus infection in the Netherlands. Both patients were immunocompromised and had pulmonary symptoms. The first patient died due to a pulmonary infection with Es. pasteurianus, concomitant listeriosis, Pseudomonas aeruginosa sepsis and invasive pulmonary aspergillosis. The second patient had pulmonary and subcutaneous lesions, and recovered completely after treatment with posaconazole for 14 months. In both cases, diagnosis of Es. pasteurianus was made with internal transcribed spacer rRNA PCR and culture. Keywords: Emergomyces, Immunocompromised, Mycosis, Disseminated infection, Dimorphic fung
    corecore