The dispensable N-terminus of iso-1-cytochrome c (iso-1) in the yeast Saccharomyces cerevisiae was replaced by 11 different amphipathic structures. Rapid degradation of the corresponding iso-1 occurred, with the degree of degradation increasing with the amphipathic moments; and this amphipathic-dependent degradation was designated ADD. ADD occurred with the holo-forms in the mitochondria but not as the apo-forms in the cytosol. The extreme mutant type degraded with a half-life of approximately 12 min, whereas the normal iso-1 was stable over hours. ADD was influenced by the rho+/rho- state and by numerous chromosomal genes. Most importantly, ADD appeared to be specifically suppressed to various extents by deletions of any of the YME1, AFG3, or RCA1 genes encoding membrane-associated mitochondrial proteases, probably because the amphipathic structures caused a stronger association with the mitochondrial inner membrane and its associated proteases. The use of ADD assisted in the differentiation of substrates of different mitochondrial degradation pathways.
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http://dx.doi.org/10.1007/s00294-004-0552-2 | DOI Listing |
ACS Nano
January 2025
Eye Center, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang Provincial Key Laboratory of Ophthalmology, Zhejiang Provincial Clinical Research Center for Eye Diseases, Zhejiang Provincial Engineering Institute on Eye Diseases, Hangzhou 310009, P. R. China.
Biofilm-related bacterial keratitis is a severe ocular infection that can result in drastic vision impairment and even blindness. However, the therapeutic efficiency of clinical antibiotic eyedrops is often compromised because the bacteria in the biofilms resist bactericide the community genetic regulation, namely, bacterial quorum sensing. Herein, quercetin (QCT)-loaded star-shaped antibacterial peptide polymer (SAPP), QCT@SAPP, is developed based on a "drug" in a "drug" strategy for inhibiting and eradicating biofilms on the cornea.
View Article and Find Full Text PDFUnlabelled: Cytoplasmic proteins must recruit to membranes to function in processes such as endocytosis and cell division. Many of these proteins recognize not only the chemical structure of the membrane lipids, but the curvature of the surface, binding more strongly to more highly curved surfaces, or 'curvature sensing'. Curvature sensing by amphipathic helices is known to vary with membrane bending rigidity, but changes to lipid composition can simultaneously alter membrane thickness, spontaneous curvature, and leaflet symmetry, thus far preventing a systematic characterization of lipid composition on such curvature sensing through either experiment or simulation.
View Article and Find Full Text PDFProtein Sci
January 2025
Institut de Biotecnologia i de Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain.
Peptides are attracting a growing interest for therapeutic applications in biomedicine. In Parkinson's disease (PD), different human endogenous peptides have been associated with beneficial effects, including protein aggregation inhibition, reduced inflammation, or the protection of dopaminergic neurons. Such effects seem to be connected to the spatial arrangement of peptide side chains, and many of these human molecules share common conformational traits, displaying a distinctive amphipathic and cationic helical structure, which is believed to be crucial for their activities.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599.
Adaptor protein complex-3 (AP-3) mediates cargo sorting from endosomes to lysosomes and lysosome-related organelles. Recently, it was shown that AP-3 adopts a constitutively open conformation compared to the related AP-1 and AP-2 coat complexes, which are inactive until undergoing large conformational changes upon membrane recruitment. How AP-3 is regulated is therefore an open question.
View Article and Find Full Text PDFNature
December 2024
Department of Physics, University of Missouri, Columbia, MO, USA.
Low-density lipoprotein (LDL) plays a central role in lipid and cholesterol metabolism and is a key agent in the development and progression of atherosclerosis, the leading cause of mortality worldwide. Apolipoprotein B100 (apoB100), one of the largest proteins in the genome, is the primary structural and functional component of LDL, yet its size and complex lipid associations have posed major challenges for structural studies. Here we present the first structure of apoB100 resolved to sub-nanometer resolution in most regions using an integrative approach of cryo-electron microscopy, AlphaFold2, and molecular dynamics-based refinement.
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