Myo-inositol hexaphosphate (IP6, phytate) is a potent anti-nutritional compound occurring in many plant-based staple foods, limiting the bioavailability of important nutrients such as iron and zinc. The objective of the present study was to investigate different strategies to achieve high and constitutive extracellular IP6 degradation by Baker's yeast, Saccharomyces cerevisiae. By deleting either of the genes PHO80 and PHO85, encoding negative regulators of the transcription of the repressible acid phosphatases (rAPs), the IP6 degradation became constitutive, and the biomass specific IP6 degradation was increased manyfold. In addition, the genes encoding the transcriptional activator Pho4p and the major rAP Pho5p were overexpressed in both a wild-type and a pho80delta strain, yielding an additional increase in IP6 degradation. It has previously been proved possible to increase human iron bioavailability by degradation of IP6 using microbial phytase. A high-phytase S. cerevisiae strain, without the use of any heterologous DNA, may be a suitable organism for the production of food-grade phytase and for the direct use in food production.
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http://dx.doi.org/10.1016/j.ijfoodmicro.2005.10.020 | DOI Listing |
J Biol Chem
December 2024
Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA; Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, Vanderbilt University Medical Center, Nashville, Tennessee, USA. Electronic address:
Mechanistic target of rapamycin (mTOR) binds the small metabolite inositol hexakisphosphate (IP) as shown in structures of mTOR; however, it remains unclear if IP, or any other inositol phosphate species, function as an integral structural element(s) or catalytic regulator(s) of mTOR. Here, we show that multiple, exogenously added inositol phosphate species can enhance the ability of mTOR and mechanistic target of rapmycin complex 1 (mTORC1) to phosphorylate itself and peptide substrates in in vitro kinase reactions, with the higher order phosphorylated species being more potent (IP = IP > IP >> IP). IP increased the V and decreased the apparent K of mTOR for ATP.
View Article and Find Full Text PDFBiophys J
January 2025
Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California. Electronic address:
The HIV-1 capsid is an irregularly shaped protein complex containing the viral genome and several proteins needed for integration into the host cell genome. Small molecules, such as the drug-like compound PF-3450074 (PF74) and the anionic sugar inositolhexakisphosphate (IP6), are known to impact capsid stability, although the mechanisms through which they do so remain unknown. In this study, we employed atomistic molecular dynamics simulations to study the impact of molecules bound to hexamers at the central pore (IP6) and the FG-binding site (PF74) on the interface between capsid oligomers.
View Article and Find Full Text PDFNutrients
November 2024
Laboratory of Clinical Nutrition and Dietetics, Department of Nutrition and Dietetics, School of Physical Education, Sport Science and Dietetics, University of Thessaly, 42100 Trikala, Greece.
Background: Phytic acid is abundant in plant-based diets and acts as a micronutrient inhibitor for humans and non-ruminant animals. Phytases are enzymes that break down phytic acid, releasing micronutrients and enhancing their bioavailability, particularly iron and zinc. Deficiencies in iron and zinc are significant public health problems, especially among populations with disease-associated malnutrition or those in developing countries consuming phytic acid-rich diets.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Institute of Future Agriculture, Northwest Agriculture and Forestry University, Yangling, Shaanxi 712100, China.
Viruses
September 2024
Department Biology, College of Arts and Sciences, American University, Washington, DC 20016, USA.
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