Staphylococcus aureus is a Gram-positive pathogen with an unusual mode of cell division in that it divides in orthogonal rather than parallel planes. Through selection using moenomycin, an antibiotic proposed to target peptidoglycan glycosyltransferases (PGTs), we have generated resistant mutants containing a single point mutation in the active site of the PGT domain of an essential peptidoglycan (PG) biosynthetic enzyme, PBP2. Using cell free polymerization assays, we show that this mutation alters PGT activity so that much shorter PG chains are made. The same mutation in another S. aureus PGT, SgtB, has a similar effect on glycan chain length. Moenomycin-resistant S. aureus strains containing mutated PGTs that make only short glycan polymers display major cell division defects, implicating PG chain length in determining bacterial cell morphology and division site placement.
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http://dx.doi.org/10.1021/cb4006744 | DOI Listing |
Chem Sci
January 2025
Centre for Membrane Separations, Adsorption, Catalysis and Spectroscopy for Sustainable Solutions (cMACS), KU Leuven Celestijnenlaan 200F, Post Box 2454 3001 Leuven Belgium
Plastic waste conversion into valuable chemicals is a promising alternative to landfill or incineration. In particular, the chemical upcycling of polybutadiene rubber (PBR) could provide a renewable route towards highly desirable α,ω-dienes with varying chain lengths, which can find ample industrial application. While previous research has shown that the treatment of polybutadiene with a consecutive hydrogenation and ethenolysis reaction can afford long-chain α,ω-dienes, achieving precise control over the product chain length remains an important bottleneck.
View Article and Find Full Text PDFFront Bioeng Biotechnol
January 2025
Pharmaceutical Development Biologicals, TIP, Boehringer Ingelheim Pharma GmbH & Co., KG, Innovation Unit, Biberach an der Riss, Germany.
Polysorbates, in particular polysorbate (PS) 20 and 80, are the most commonly used surfactants for stabilising biotherapeutics produced by biotechnological processes. PSs are derived from ethoxylated sorbitan (a derivative of sorbitol) esterified with fatty acids of varying chain length and degree of saturation. In the past, these surfactants have been reported to have specific liabilities.
View Article and Find Full Text PDFPept Sci (Hoboken)
November 2024
Department of Pediatrics, Section of Hematology/Oncology, The University of Chicago, Chicago, Illinois 60637, United States of America.
The COVID-19 pandemic drove a uniquely fervent pursuit to explore the potential of peptide, antibody, protein, and small-molecule based antiviral agents against severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). The interaction between the SARS-CoV2 spike protein with the angiotensin-converting enzyme 2 (ACE2) receptor that mediates viral cell entry was a particularly interesting target given its well described protein-protein interaction (PPI). This PPI is mediated by an α-helical portion of ACE2 binding to the receptor binding domain (RBD) of the spike protein and thought to be susceptible to blockade through molecular mimicry.
View Article and Find Full Text PDFBayesian Anal
June 2024
Department of Statistics, Purdue University, West Lafayette, IN 47907, USA.
The exponential random graph model (ERGM) is a popular model for social networks, which is known to have an intractable likelihood function. Sampling from the posterior for such a model is a long-standing problem in statistical research. We analyze the performance of the stochastic gradient Langevin dynamics (SGLD) algorithm (also known as noisy Longevin Monte Carlo) in tackling this problem, where the stochastic gradient is calculated via running a short Markov chain (the so-called inner Markov chain in this paper) at each iteration.
View Article and Find Full Text PDFChem Asian J
January 2025
Chulalongkorn University, Chemistry, THAILAND.
This research focuses on the selective detection of Hg2+ ions using hybrid nanosensors composed of rhodamine building blocks linked to polyamine units of varying chain lengths to produce Rho1-Rho4, which were subsequently conjugated with thioctic acid (RT1-RT4) and attached to the surface of gold nanoparticles to create hybrid nanosensors (GRT1-GRT4) designed for detecting heavy metals. The chemical structures, purity, morphology, and chemical composition were characterized through XRD, NMR, TEM, ATR-FTIR, and mass spectrometry. These hybrid nanosensors demonstrated excellent selectivity and sensitivity in colorimetric and fluorescence responses towards Hg2+, outperforming other metal ions.
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