Proteins linked to cell membranes by a glycosylphosphatidylinositol (GPI) anchor must first undergo cleavage by a putative transamidase between the omega and omega + 1 positions within a proposed small amino acid (SAD) domain in the carboxy terminus of the nascent polypeptide. The requirements for such processing, defined in an engineered placental alkaline phosphatase construct (miniPLAP), suggest the SAD domain functions as an autonomous unit within the context of an otherwise permissive carboxy-terminal sequence with only certain amino acids tolerated at the omega, omega + 1, and omega + 2 positions. To test whether this hypothesis could be generalized, we engineered a chimeric molecule containing the extracellular domain of miniPLAP and the carboxy-terminal portion of the urokinase receptor (MP/uPAR) into which various amino acid substitutions were introduced. The variant proteins were translated and metabolically labeled in vitro using a cell-free translation system that contains the enzymatic machinery required for carboxy-terminal processing and GPI anchor addition. The results of this study indicate that the SAD domain functions as an independent, but not an autonomous, unit. The requirements for processing in miniPLAP and MP/uPAR differed markedly in some respects, in part due to the influence of the amino acid at the omega + 4 position which both modified cleavage between the omega and omega + 1 positions and permitted a second cleavage site to be generated in some cases. In addition, substitution of bulky hydrophobic amino acids in series at the omega + 2 and omega + 3 positions inhibited carboxy-terminal processing in a dose-dependent manner, suggesting the presence of a critical docking site adjacent to the cleavage site. These results suggest the carboxy-terminal transamidase recognizes a more extended structure similar to the mechanism proposed for serine proteases. Further, the data provide a potential means for isolating the transamidase.
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http://dx.doi.org/10.1021/bi9810914 | DOI Listing |
PLoS One
January 2025
Department of Nutrition and Public Health, Faculty of Health and Sport Science, University of Agder, Kristiansand, Norway.
Background: Knowledge about the diet quality among youth who follow different types of plant-based diets is essential to understand whether support is required to ensure a well-planned diet that meets their nutritional needs. This study aimed to investigate how food groups, macronutrient intake, and objective blood measures varied between Norwegian youth following different plant-based diets compared to omnivorous diet.
Methods: Cross-sectional design, with healthy 16-to-24-year-olds (n = 165) recruited from the Agder area in Norway, following a vegan, lacto-ovo-vegetarian, pescatarian, flexitarian or omnivore diet.
Plant Physiol
January 2025
Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546-0312, USA.
Omega (ω)-3 fatty acids (FAs) are essential components of cell membranes that also serve as precursors of numerous regulatory molecules. α-linolenic acid (ALA), one of the most important ω3 FAs in plants, is synthesized in both the plastid and extraplastidial compartments. FA Desaturase (FAD) 3 is an extraplastidial enzyme that converts linoleic acid (LA) to ALA.
View Article and Find Full Text PDFNutr Rev
January 2025
Universidad Europea de Madrid, Department of Physiotherapy, Faculty of Medicine, Health and Sports, 28670 Villaviciosa de odón, Madrid, Spain.
Context: Migraines are a prevalent neurological condition that significantly impacts the quality of life. Although narrative reviews and clinical trials suggest the potential effects of fatty acid supplementation as a promising approach for migraine prophylaxis, the findings remain inconsistent.
Objective: The aim was to evaluate the efficacy of fatty acid supplementation on migraine clinical outcomes through a systematic review and meta-analysis.
Gastroenterol Res Pract
January 2025
Department of Gastroenterology, Tongji Institute of Digestive Diseases, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China.
This study is aimed at comparing the clinical characteristics and histological types of symptomatic and asymptomatic patients with heterotopic gastric mucosa in the upper esophagus (HGMUE) and exploring the factors influencing the occurrence and severity of laryngopharyngeal reflux (LPR) symptoms in these patients. HGMUE is a potential cause of LPR symptoms. This retrospective analysis evaluated 70 patients with HGMUE using a detailed questionnaire.
View Article and Find Full Text PDFEduc Psychol Meas
January 2025
Yale University, New Haven, CT, USA.
An index extending the widely used omega-hierarchical coefficient is discussed, which can be used for evaluating the influence of a second-order factor on the interrelationships among the components of a hierarchical measuring instrument. The index represents a useful and informative complement to the traditional omega-hierarchical measure of explained overall scale score variance by that underlying construct. A point and interval estimation procedure is outlined for the described index, which is based on model reparameterization and is developed within the latent variable modeling framework.
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