The integral membrane protein BlaR1 of methicillin-resistant Staphylococcus aureus senses the presence of β-lactam antibiotics in the milieu and transduces the information to the cytoplasm, where the biochemical events that unleash induction of antibiotic resistance mechanisms take place. We report herein by two-dimensional and three-dimensional NMR experiments of the sensor domain of BlaR1 in solution and by determination of an x-ray structure for the apo protein that Lys-392 of the antibiotic-binding site is posttranslationally modified by N(ζ)-carboxylation. Additional crystallographic and NMR data reveal that on acylation of Ser-389 by antibiotics, Lys-392 experiences N(ζ)-decarboxylation. This unique process, termed the lysine N(ζ)-decarboxylation switch, arrests the sensor domain in the activated ("on") state, necessary for signal transduction and all the subsequent biochemical processes. We present structural information on how this receptor activation process takes place, imparting longevity to the antibiotic-receptor complex that is needed for the induction of the antibiotic-resistant phenotype in methicillin-resistant S. aureus.
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http://dx.doi.org/10.1074/jbc.M111.252189 | DOI Listing |
Mol Cell
December 2024
Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA; Department of Molecular Biology, University of California, San Diego, La Jolla, CA, USA. Electronic address:
Prokaryotes possess diverse anti-bacteriophage immune systems, including the single-protein Shedu nuclease. Here, we reveal the structural basis for activation of Bacillus cereus Shedu. Two cryoelectron microscopy structures of Shedu show that it switches between inactive and active states through conformational changes affecting active-site architecture, which are controlled by the protein's N-terminal domain (NTD).
View Article and Find Full Text PDFLight Sci Appl
January 2025
State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Electronics, Peking University, Beijing, 100871, China.
Metamaterials have revolutionized wave control; in the last two decades, they evolved from passive devices via programmable devices to sensor-endowed self-adaptive devices realizing a user-specified functionality. Although deep-learning techniques play an increasingly important role in metamaterial inverse design, measurement post-processing and end-to-end optimization, their role is ultimately still limited to approximating specific mathematical relations; the metamaterial is still limited to serving as proxy of a human operator, realizing a predefined functionality. Here, we propose and experimentally prototype a paradigm shift toward a metamaterial agent (coined metaAgent) endowed with reasoning and cognitive capabilities enabling the autonomous planning and successful execution of diverse long-horizon tasks, including electromagnetic (EM) field manipulations and interactions with robots and humans.
View Article and Find Full Text PDFEnviron Technol
December 2024
College of Mechanical and Electrical Engineering, China Jiliang University, Hangzhou, People's Republic of China.
The moisture content (MC) of sludge is a critical factor affecting sludge treatment and disposal technologies. Traditional drying methods for measuring sludge MC are time-consuming and lack of portability. To achieve rapid online detection of sludge MC, this paper proposes a method based on frequency domain reflectometry.
View Article and Find Full Text PDFEcol Lett
December 2024
Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA.
Identifying the scaling rules describing ecological patterns across time and space is a central challenge in ecology. Taylor's law of fluctuation scaling, which states that the variance of a population's size or density is proportional to a positive power of the mean size or density, has been widely observed in population dynamics and characterizes variability in multiple scientific domains. However, it is unclear if this phenomenon accurately describes ecological patterns across many orders of magnitude in time, and therefore links otherwise disparate observations.
View Article and Find Full Text PDFEnviron Monit Assess
December 2024
Institute for Life Sciences and the Environment, University of Southern Queensland, Toowoomba, Queensland, 4350, Australia.
Military operations have long been recognized to cause significant environmental consequences. However, research on the environmental impacts of military operations remains fragmented despite the rise of modern technologies, including remote sensing (RS) and geographic information system (GIS). Hence, this study sought to review the literature on using RS and GIS approaches to assess military operations' environmental impacts.
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