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Daptomycin is a lipopeptide antibiotic that is important in the treatment of infections with Gram-positive bacteria. In the presence of calcium, daptomycin binds to phosphatidylglycerol in the bacterial cytoplasmic membrane and then forms oligomers that mediate its bactericidal effect. The structure of these bactericidal oligomers has not been elucidated. We here explore the feasibility of structural studies on the oligomer by solution-state NMR. To this end, we use nanodiscs that contain DMPC and DMPG, stabilized with a styrene-maleic acid copolymer that has been modified to minimize calcium chelation. We show that these nanodiscs bind daptomycin and induce the formation of stable oligomers under physiologically relevant conditions. The findings suggest that this membrane model is suitable for structural and functional characterization of oligomeric daptomycin, and possibly of other calcium-dependent lipopeptide antibiotics. We show that these nanodiscs bind daptomycin and induce the formation of stable oligomers, under conditions that are suitable for biomolecular NMR. The findings suggest that this membrane model is suitable for structural elucidation of oligomeric daptomycin, and possibly of other calcium-dependent lipopeptide antibiotics.
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http://dx.doi.org/10.1016/j.bbamem.2020.183234 | DOI Listing |
Methods
September 2025
Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute of Physical Biology, Universitätsstr. 1, 40225 Düsseldorf, Germany; Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany; Jülich Ce
Many membrane proteins, including G protein-coupled receptors (GPCRs), are susceptible to denaturation when extracted from their native membrane by detergents. Therefore, alternative methods have been developed, including amphiphilic copolymers that enable the direct extraction of functional membrane proteins along with their surrounding lipids. Among these amphiphilic copolymers, styrene/maleic acid (SMA) and diisobutylene/maleic acid (DIBMA) polymers have been extensively studied.
View Article and Find Full Text PDFYakugaku Zasshi
August 2025
Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University.
Biopharmaceutics Classification System Class II and IV drugs face significant challenges owing to poor water solubility, restricting their formulation in liquid delivery forms. The use of polymers, including the loading of drugs into nanoparticles, has attracted attention as an effective strategy for improving the solubility of poorly water-soluble drugs. These polymer carrier systems possess a hydrophilic outer shell and a hydrophobic inner core that can encapsulate poorly water-soluble drugs and improve their dispersibility in aqueous environments.
View Article and Find Full Text PDFAnal Bioanal Chem
August 2025
College of Pharmaceutical Sciences, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis, Ministry of Education, Hebei University, Baoding, 071002, China.
Phospholipids have been considered biomarkers for diagnosing many diseases in recent years. However, the isolation and analysis of phospholipids still face many difficulties. Styrene-maleic acid (SMA) copolymer is currently considered suitable for the separation and analysis of phospholipids due to its ability to enhance and improve the solubility of phospholipid bilayers on cell membranes.
View Article and Find Full Text PDFCurr Opin Struct Biol
August 2025
Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23298-0540, USA; Center for Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298-0133, USA. Electronic address:
The native cell membrane nanoparticles (NCMN) system utilizes membrane-active polymers specifically designed and optimized to extract and stabilize membrane proteins in the form of NCMN particlesfor biochemical and biophysical characterization. The NCMN system is a genuine and advanced detergent-free approach inspired by the membrane activity of the styrene-maleic acid copolymers (SMA), distinguishing it from the nanodisc technology, Salipro technology, and Peptidisc technology. This review introduces the current advancements in the NCMN system, including the development of NCMN polymers, the application of the NCMN system for single-particle cryo-EM analysis, and the functional characterization of membrane proteins.
View Article and Find Full Text PDFBiol Pharm Bull
July 2025
Laboratory of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Sojo University, 4-22-1 Ikeda, Nishi-ku, Kumamoto 860-0082, Japan.
Matrix metalloproteinases (MMPs), specifically MMP-2 and MMP-9, play a significant role in tumor growth and malignancy. Therefore, measuring their activity in vivo could enhance the diagnosis and treatment of cancer. Given the medical and pharmaceutical applications of the in vivo ESR techniques in recent decades, we developed a probe to evaluate MMP activity based on ESR spectral changes that depend on the rotational correlation time of the nitroxyl radical.
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