Dehydrophos is a tripeptide phosphonate antibiotic produced by Streptomyces luridus. Its biosynthetic pathway involves the use of aminoacyl-tRNA (aa-tRNA) for amide bond formation. The first amide bond during biosynthesis is formed by DhpH-C, a peptidyltransferase that utilizes Leu-tRNA. DhpH-C is a member of a burgeoning family of natural product biosynthetic enzymes that make use of aa-tRNA outside of canonical translation activities in the cell. Here, we used site-directed mutagenesis of both DhpH-C and tRNA to investigate the enzyme mechanism and substrate specificity, respectively, and analyzed the substrate scope for the production of a set of dipeptides. DhpH-C appears to recognize both the amino acyl group on the tRNA and the tRNA acceptor stem, and the enzyme can accept other hydrophobic residues, in addition to leucine. These results contribute to a better understanding of enzyme-aa-tRNA interactions and the growing exploration of aa-tRNA usage beyond translation.
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http://dx.doi.org/10.1021/acschembio.7b00949 | DOI Listing |
Molecules
January 2025
Department of Chemistry, Acadia University, Wolfville, NS B4P 2R6, Canada.
A concise, transition metal-free four-step synthetic pathway has been developed for the synthesis of tetracyclic heterosteroidal compounds, 14-aza-12-oxasteroids, starting from readily available 2-naphthol analogues. After conversion of 2-naphthols to 2-naphthylamines by the Bucherer reaction, subsequent selective C-acetylation was achieved via the Sugasawa reaction and reduction of the acetyl group using borohydride, which resulted into the corresponding amino-alcohols. The naphthalene-based amino-alcohols underwent double dehydrations and double intramolecular cyclization with oxo-acids leading to one-pot formation of a C-N bond, a C-O bond and an amide bond in tandem, to generate two additional rings completing the steroidal framework.
View Article and Find Full Text PDFJ Environ Sci (China)
July 2025
School of Environmental Science and Engineering, Shandong Key Laboratory of Environmental Processes and Health, Shandong University, Qingdao 266237, China; Laboratory of Marine Ecological Environment in Universities of Shandong, Shandong University, Qingdao 266237, China; Qingdao Key Laboratory of Marine Pollutant Prevention, Shandong University, Qingdao 266237, China; Shandong Kenli Petrochemical Group Co., Ltd., Dongying 257500, China. Electronic address:
Due to the endocrine toxicity, neurotoxic, and reproductive toxicity to organisms, the sources and risks of brominated organic pollutants have attracted widespread attention. However, knowledge gaps remain in the bromination processes of emerging phenolic pollutants in plants, which may increase the potential health risk associated with food exposure. Our study discovered that light induced generation and accumulation of more toxic brominated organic compounds (Br-org) in lettuce leaves under the stress of acetaminophen (ACE) than that without light, as evidenced by an increase in C-Br bond intensity in FTIR analysis.
View Article and Find Full Text PDFNat Commun
January 2025
School of Materials Science and Chemical Engineering, Institute of Drug Discovery Technology, Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo, PR China.
C-C bond cleavage and recombination provide an efficient strategy for the modification and reconstruction of molecule structures. Herein, we present a method for achieving amidation of aryl C(sp)-H bond through the cleavage and recombination of C-C triple bond with the involvement of nitrous acid esters. This method marks the instance of precise and controlled stepwise cleavage of C-C triple bond, offering a fresh perspective for the cleavage of such bonds.
View Article and Find Full Text PDFInorg Chem
January 2025
Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States.
Herein, we investigate the effects of ligand design on the nuclearity and reactivity of metal-ligand multiply bonded (MLMB) complexes to access an exclusively bimetallic reaction pathway for C-H bond functionalization. To this end, the diiron alkoxide [Fe(Dbf)] () was treated with 3,5-bis(trifluoromethyl)phenyl azide to access the diiron imido complex [Fe(Dbf)(μ-NCHF)] () that promotes hydrogen atom abstraction (HAA) from a variety of C-H and O-H bond containing substrates. A diiron bis(amide) complex [Fe(Dbf)(μ-NHCHF)(NHCHF)] () was generated, prompting the isolation of the analogous bridging amide terminal alkoxide [Fe(Dbf)(μ-NHCHF)(OCH)] () and the asymmetric pyridine-bound diiron imido [Fe(Dbf)(μ-NCHF)(NCH)] ().
View Article and Find Full Text PDFBiochemistry
January 2025
Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States.
is the leading cause of food poisoning in Europe and North America. The exterior surface of this bacterium is encased by a capsular polysaccharide that is attached to a diacyl glycerol phosphate anchor via a poly-Kdo (3-deoxy-d--oct-2-ulosinic acid) linker. In the HS:2 serotype of NCTC 11168, the repeating trisaccharide consists of d-ribose, -acetyl-d-glucosamine, and d-glucuronate.
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