The cellular process of intrinsic apoptosis relies on the peroxidation of mitochondrial lipids as a critical molecular signal. Lipid peroxidation is connected to increases in mitochondrial reactive oxygen species, but there is also a required role for mitochondrial cytochrome c (cyt-c). In apoptotic mitochondria, cyt-c gains a new function as a lipid peroxidase that catalyzes the reactive oxygen species-mediated chemical modification of the mitochondrial lipid cardiolipin (CL). This peroxidase activity is caused by a conformational change in the protein, resulting from interactions between cyt-c and CL. The nature of the conformational change and how it causes this gain-of-function remain uncertain. Via a combination of functional, structural, and biophysical experiments we investigate the structure and peroxidase activity of cyt-c in its membrane-bound state. We reconstituted cyt-c with CL-containing lipid vesicles, and determined the increase in peroxidase activity resulting from membrane binding. We combined these assays of CL-induced proapoptotic activity with structural and dynamic studies of the membrane-bound protein via solid-state NMR and optical spectroscopy. Multidimensional magic angle spinning (MAS) solid-state NMR of uniformly (13)C,(15)N-labeled protein was used to detect site-specific conformational changes in oxidized and reduced horse heart cyt-c bound to CL-containing lipid bilayers. MAS NMR and Fourier transform infrared measurements show that the peripherally membrane-bound cyt-c experiences significant dynamics, but also retains most or all of its secondary structure. Moreover, in two-dimensional and three-dimensional MAS NMR spectra the CL-bound cyt-c displays a spectral resolution, and thus structural homogeneity, that is inconsistent with extensive membrane-induced unfolding. Cyt-c is found to interact primarily with the membrane interface, without significantly disrupting the lipid bilayer. Thus, membrane binding results in cyt-c gaining the increased peroxidase activity that represents its pivotal proapoptotic function, but we do not observe evidence for large-scale unfolding or penetration into the membrane core.
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http://dx.doi.org/10.1016/j.bpj.2015.09.016 | DOI Listing |
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Department of School of Pharmaceutical Sciences, Changchun University of Chinese Medicine, Changchun, China.
To explore the antioxidant activity of enzymatic hydrolysates of from Dalian and preliminarily elucidate their mechanisms of action both and . Samples were hydrolysed using alcalase, protamex, and neutrase. 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assays showed that the alcalase hydrolysate had the highest antioxidant activity, with IC values of 4.
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January 2025
Faculty of Sport Sciences, Near East University, Nicosia, Cyprus.
Abundant evidence indicates that skeletal muscle plays a key role in regulating metabolic homeostasis. Therefore, maintaining healthy skeletal muscles is essential to good health. While prolonged muscle inactivity is known to cause oxidative stress and muscle loss, it remains unclear whether a shift from an active to a sedentary lifestyle induces similar effects.
View Article and Find Full Text PDFInsect Sci
January 2025
College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China.
Our previous study shows that Coptotermes formosanus (Blattodea: Rhinotermitidae) preferred to stay on filter paper treated with ethyl 2,4-dioxovalerate, a metabolite in the soil fungus Trichoderma virens. Here, we hypothesized that adding ethyl 2,4-dioxovalerate in sand could trigger aggregation and tunneling preferences of C. formosanus and improve the effectiveness of liquid termiticide.
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January 2025
Limited Liability Company "Pyatigorsk Dairy Plant", 357500, Pyatigorsk, Russian Federation.
To level out the nutrient imbalance in diets, patients with carbohydrate and lipid metabolism disorders are prescribed to include specialized low-fat food with increased protein content. In this regard, the development and evaluation of the effectiveness of such products enriched with micronutrients is relevant. of the research was to evaluate the clinical effectiveness of a specialized fermented milk product for the dietary correction of carbohydrate and fat metabolism disorders.
View Article and Find Full Text PDFCureus
December 2024
Internal Medicine, University of Alexandria, Alexandria, EGY.
Aim: Thyroid nodules, based on high-resolution ultrasonography (HRUS), are among the most common endocrine abnormalities that affect the general population because of their high estimated prevalence rates. Fine needle aspiration cytology (FNAC) is a safe, cost-effective modality to differentiate between benign and malignant thyroid nodules based on the Bethesda System for Reporting Thyroid Cytopathology (BSRTC), thus avoiding unnecessary surgery. However, categories III and IV of BSRTC remain a controversial issue in clinical practice, encompassing a wide range of risks of malignancy.
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