Sulfur, a key contributor to biological reactivity, is not amendable to investigations by biological NMR spectroscopy. To utilize selenium as a surrogate, we have developed a generally applicable (77)Se isotopic enrichment method for heterologous proteins expressed in Escherichia coli. We demonstrate (77)Se NMR spectroscopy of multiple selenocysteine and selenomethionine residues in the sulfhydryl oxidase augmenter of liver regeneration (ALR). The resonances of the active-site residues were assigned by comparing the NMR spectra of ALR bound to oxidized and reduced flavin adenine dinucleotide. An additional resonance appears only in the presence of the reducing agent and disappears readily upon exposure to air and subsequent reoxidation of the flavin. Hence, (77)Se NMR spectroscopy can be used to report the local electronic environment of reactive and structural sulfur sites, as well as changes taking place in those locations during catalysis.
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http://dx.doi.org/10.1016/j.jmb.2012.11.011 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
University of Regensburg, Faculty of Chemistry and Pharmacy, Institute of Inorganic Chemistry, Universitätsstraße 31, D-93053, Regensburg, GERMANY.
Aminophosphates are the focus of research on prebiotic phosphorylation chemistry. Their bifunctional nature also makes them a powerful class of organocatalysts. However, the structural chemistry and dynamics of proton-binding in phosphorylation and organocatalytic mechanisms are still not fully understood.
View Article and Find Full Text PDFSchizophr Bull
January 2025
Psychotic Disorders Division, McLean Hospital, Belmont, MA, United States.
Background And Hypothesis: Convergent evidence shows the presence of brain metabolic abnormalities in psychotic disorders. This study examined brain reductive stress and energy metabolism in people with psychotic disorders with impaired or average range cognition. We hypothesized that global cognitive impairment would be associated with greater brain metabolic dysregulation.
View Article and Find Full Text PDFLangmuir
January 2025
College of Bioresources Chemical and Materials Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China.
A novel pH-responsive full-bio-based surfactant (Ca-S) containing a dynamic covalent bond is synthesized using renewable cashew phenol, 5-chloro-2-furanaldehyde, and taurine. The structure of Ca-S is characterized by Fourier transform infrared spectroscopy (FTIR) and H nuclear magnetic resonance (NMR) analysis. Limonene containing oil-in-water (O/W) microemulsions are prepared on the basis of the Ca-S surfactant and are applied to the remediation of oil-contaminated soil under low-energy conditions at ambient temperature.
View Article and Find Full Text PDFEur J Neurol
February 2025
Department of Biomedical and NeuroMotor Sciences, University of Bologna, Bologna, Italy.
Objective: Disorders of arousal (DoA) are characterized by an intermediate state between wakefulness and deep sleep, leading to incomplete awakenings from NREM sleep. Multimodal studies have shown subtle neurophysiologic alterations even during wakefulness in DoA. The aim of this study was to explore the brain functional connectivity in DoA and the metabolic profile of the anterior and posterior cingulate cortex, given its pivotal role in cognitive and emotional processing.
View Article and Find Full Text PDFRSC Adv
January 2025
Dipartimento di Scienze e Innovazione Tecnologica, Università Del Piemonte Orientale A. Avogadro Viale T. Michel 11 15121 Alessandria Italy
A novel synthesis of a nanometric MCM-41 from biogenic silica obtained from rice husk is here presented. CTABr and Pluronic F127 surfactants were employed as templating agents to promote the formation of a long-range ordered 2D-hexagonal structure with cylindrical pores and to limit the particle growth at the nanoscale level thus resulting in a material with uniform particle size of 20-30 nm. The physico-chemical properties of this sample (RH-nanoMCM) were investigated through a multi-technique approach, including PXRD, Si MAS NMR, TEM, -potential and N physisorption analysis at 77 K.
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