The Role of the Tight-Turn, Broken Hydrogen Bonding, Glu222 and Arg96 in the Post-translational Green Fluorescent Protein Chromophore Formation

Green fluorescent proteins (GFP) and GFP-like proteins all undergo an autocatalytic post-translational modification to form a centrally located chromophore. Structural analyses of all the GFP and GFP-like proteins in the protein databank were undertaken to determine the role of the tight-turn, broken hydrogen bonding, Gly67, Glu222 and Arg96 in the biosynthesis of the imidazolone group from 65SYG67. The analysis was supplemented by computational generation of the conformation adopted by uncyclized wild-type GFP. The data analysis suggests that Arg96 interacts with the Tyr66 carbonyl, stabilizing the reduced enolate intermediate that is required for cyclization; the carboxylate of Glu222 acts as a base facilitating, through a network of two waters, the abstraction of a hydrogen from the α-carbon of Tyr66; a tight-turn conformation is required for autocatalytic cyclization. This conformation is responsible for a partial reduction in the hydrogen bonding network around the chromophore-forming region of the immature protein

Wild-type and mutant SOD1 share an aberrant conformation and a common pathogenic pathway in ALS.

Many mutations confer one or more toxic function(s) on copper/zinc superoxide dismutase 1 (SOD1) that impair motor neuron viability and cause familial amyotrophic lateral sclerosis (FALS). Using a conformation-specific antibody that detects misfolded SOD1 (C4F6), we found that oxidized wild-type SOD1 and mutant SOD1 share a conformational epitope that is not present in normal wild-type SOD1. In a subset of human sporadic ALS (SALS) cases, motor neurons in the lumbosacral spinal cord were markedly C4F6 immunoreactive, indicating that an aberrant wild-type SOD1 species was present. Recombinant, oxidized wild-type SOD1 and wild-type SOD1 immunopurified from SALS tissues inhibited kinesin-based fast axonal transport in a manner similar to that of FALS-linked mutant SOD1. Our findings suggest that wild-type SOD1 can be pathogenic in SALS and identify an SOD1-dependent pathogenic mechanism common to FALS and SALS

Sensory Communication

Contains table of contents for Section 2, an introduction and reports on fifteen research projects.National Institutes of Health Grant RO1 DC00117National Institutes of Health Grant RO1 DC02032National Institutes of Health Contract P01-DC00361National Institutes of Health Contract N01-DC22402National Institutes of Health/National Institute on Deafness and Other Communication Disorders Grant 2 R01 DC00126National Institutes of Health Grant 2 R01 DC00270National Institutes of Health Contract N01 DC-5-2107National Institutes of Health Grant 2 R01 DC00100U.S. Navy - Office of Naval Research/Naval Air Warfare Center Contract N61339-94-C-0087U.S. Navy - Office of Naval Research/Naval Air Warfare Center Contract N61339-95-K-0014U.S. Navy - Office of Naval Research/Naval Air Warfare Center Grant N00014-93-1-1399U.S. Navy - Office of Naval Research/Naval Air Warfare Center Grant N00014-94-1-1079U.S. Navy - Office of Naval Research Subcontract 40167U.S. Navy - Office of Naval Research Grant N00014-92-J-1814National Institutes of Health Grant R01-NS33778U.S. Navy - Office of Naval Research Grant N00014-88-K-0604National Aeronautics and Space Administration Grant NCC 2-771U.S. Air Force - Office of Scientific Research Grant F49620-94-1-0236U.S. Air Force - Office of Scientific Research Agreement with Brandeis Universit

Practice effects in nutrition intervention studies with repeated cognitive testing

There is growing interest in the use of nutrition interventions to improve cognitive function. To determine intervention efficacy, repeated cognitive testing is often required. However, performance on tasks can improve through practice, irrespective of any intervention.This study investigated practice effects for commonly used cognitive tasks (immediate and delayed recall, serial subtractions, Stroop and the Sternberg task) to identify appropriate methodology for minimising their impact on nutrition intervention outcomes.Twenty-nine healthy young adults completed six repetitions of the cognitive battery (two sessions on each of three separate visits). Subjective measures of mood, motivation and task difficulty were also recorded at each repetition.Significant practice effects were apparent for all tasks investigated and were attenuated, but not fully eliminated, at later visits compared with the earlier visits. Motivation predicted cognitive performance for the tasks rated most difficult by participants (serial 7s, immediate and delayed recall). While increases in mental fatigue and corresponding decreases in positive mood were observed between test sessions occurring on the same day, there were no negative consequences of long term testing on mood across the duration of the study.Practice effects were evident for all investigated cognitive tasks, with strongest effects apparent between visits one and two. Methodological recommendations to reduce the impact of practice on the statistical power of future intervention studies have been made, including the use of alternate task forms at each repetition and the provision of a familiarisation visit on a separate day prior to data collection

Faithful chaperones

This review describes the properties of some rare eukaryotic chaperones that each assist in the folding of only one target protein. In particular, we describe (1) the tubulin cofactors, (2) p47, which assists in the folding of collagen, (3) α-hemoglobin stabilizing protein (AHSP), (4) the adenovirus L4-100 K protein, which is a chaperone of the major structural viral protein, hexon, and (5) HYPK, the huntingtin-interacting protein. These various-sized proteins (102–1,190 amino acids long) are all involved in the folding of oligomeric polypeptides but are otherwise functionally unique, as they each assist only one particular client. This raises a question regarding the biosynthetic cost of the high-level production of such chaperones. As the clients of faithful chaperones are all abundant proteins that are essential cellular or viral components, it is conceivable that this necessary metabolic expenditure withstood evolutionary pressure to minimize biosynthetic costs. Nevertheless, the complexity of the folding pathways in which these chaperones are involved results in error-prone processes. Several human disorders associated with these chaperones are discussed

Modélisation de la Génération et de la Propagation des Chocs Mécaniques dans les Structures Spatiales

International audienceIn space systems, mechanical shock is a crucial factor in defining specifications. Accurately predicting the shock levels expected during flight and ensuring the equipment's resistance to these levels is essential. This paper aims to present research focused on developing effective methods for modeling mechanical shocks in space systems. This study is part of a PhD thesis entitled "Modeling the Propagation and Generation of Mechanical Shocks in Space Structures."Pour les systèmes spatiaux, les chocs mécaniques représentent une source de spécification importante. Il est essentiel de prédire les niveaux attendus en vol et la tenue des équipements à ces niveaux de chocs spécifiés. L’objectif de cette communication est donc de présenter les recherches menées pour établir des méthodes efficaces de modélisation des chocs mécaniques dans les systèmes spatiaux. Ce travail s’inscrit dans une thèse de doctorat intitulée « Modélisation de la propagation et de la génération des chocs mécaniques dans les structures spatiales

Long-Term Risk Factors for Occult Cancer Detection in Patients with Unprovoked Venous Thromboembolism: A Post-Hoc Analysis of the Reverse Study

Abstract Background: The diagnosis of an unprovoked (i.e., in the absence of any risk factors) venous thromboembolism (VTE) may be a sign of an underlying cancer. Previous estimates of the incidence rate of occult cancer in patients with unprovoked VTE are as high as 5-10%. However, screening methods to detect cancer early in these patients are of limited clinical value and previous identification of risk factors focused on short-term cancer diagnosis. Therefore, this study will assess the long-term incidence and risk factors of cancer in unprovoked VTE patients. Methods: This retrospective study is a post-hoc analysis of the REVERSE (Recurrent Venous Thromboembolism Risk Stratification Evaluation) study. Patient data was collected following an initial six-month course of anticoagulation therapy and were followed for a mean time period of 5.0 years (range 1 month-8 years). We performed univariable analysis to test the strength of association between each potential predictor variable and occult cancer diagnosis. Furthermore, using forward model selection we created a multivariable model with optimal predictive value for cancer diagnosis. Results: Among 663 patients presenting with unprovoked VTE, 38 (5.7%) subsequently developed a new cancer diagnosis during the follow-up period. The most common types of cancers diagnosed were prostate (21%) and colorectal cancer (16%). Univariate analysis revealed age &gt; 65 (OR 2.59; 95% CI 1.31-4.49, P= 0.0036), elevated D-Dimer (OR 2.71; 95% CI 1.38-5.31, P=0.026) and pulmonary vein obstruction (PVO) score (OR 4.34 95% CI 1.26-14.92, P=0.023) as the strongest predictors of occult cancer. Only D-Dimer (Adj.-OR 2.72 95% CI 1.39-5.32) remained in the multivariate model and no other factor significantly improved the model's fit. Conclusion: Patients with an unprovoked VTE remain at an elevated risk of developing cancer following anticoagulation therapy. Age &gt; 65 years old, elevated D-Dimer, and PVO in pulmonary embolism patients are among potential risk factors for developing occult cancer. More studies are needed to validate these potentially important risk factors. Disclosures Carrier: BMS: Honoraria, Research Funding; Leo Pharma: Research Funding; Pfizer: Honoraria; Bayer: Honoraria. Rodger:Biomerieux: Research Funding. Kovacs:Daiichi Sankyo Pharma Development: Research Funding; Bayer: Research Funding. </jats:sec

Comparative analysis of alternative polyadenylation in <i>S. cerevisiae</i> and <i>S. pombe</i>

Alternative polyadenylation (APA) is a widespread mechanism that generates mRNA isoforms with distinct properties. Here we have systematically mapped and compared cleavage and polyadenylation sites (PASs) in two yeast species, S. cerevisiae and S. pombe. Although &gt;80% of the mRNA genes in each species were found to display APA, S. pombe showed greater 3′ UTR size differences among APA isoforms than did S. cerevisiae. PASs in different locations of gene are surrounded with distinct sequences in both species and are often associated with motifs involved in the Nrd1-Nab3-Sen1 termination pathway. In S. pombe, strong motifs surrounding distal PASs lead to higher abundances of long 3′ UTR isoforms than short ones, a feature that is opposite in S. cerevisiae. Differences in PAS placement between convergent genes lead to starkly different antisense transcript landscapes between budding and fission yeasts. In both species, short 3′ UTR isoforms are more likely to be expressed when cells are growing in nutrient-rich media, although different gene groups are affected in each species. Significantly, 3′ UTR shortening in S. pombe coordinates with up-regulation of expression for genes involved in translation during cell proliferation. Using S. pombe strains deficient for Pcf11 or Pab2, we show that reduced expression of 3′-end processing factors lengthens 3′ UTR, with Pcf11 having a more potent effect than Pab2. Taken together, our data indicate that APA mechanisms in S. pombe and S. cerevisiae are largely different: S. pombe has many of the APA features of higher species, and Pab2 in S. pombe has a different role in APA regulation than its mammalian homolog, PABPN1.</jats:p