98%
921
2 minutes
20
Pyridoxal 5'-phosphate (PLP)-dependent enzymes are a group of versatile enzymes that catalyze various reactions, but only a small number of them react with O. Here, we report an unprecedented PLP-dependent enzyme, NphE, that catalyzes both transamination and two-electron oxidation using O as an oxidant. Our intensive analysis reveals that NphE transfers the l-glutamate-derived amine to 1,3,6,8-tetrahydroxynaphthalene-derived mompain to form 8-amino-flaviolin (8-AF) via a highly conjugated quinonoid intermediate that is reactive with O. During the NphE reaction, O is reduced to yield HO. An integrated technique involving NphE structure prediction by AlphaFold v2.0 and molecular dynamics simulation suggested the O-accessible cavity. Our in vivo results demonstrated that 8-AF is a genuine biosynthetic intermediate for the 1,3,6,8-tetrahydroxynaphthalene-derived meroterpenoid naphterpin without an amino group, which was supported by site-directed mutagenesis. This study clearly establishes the NphE reaction product 8-AF as a common intermediate with a cryptic amino group for the biosynthesis of terpenoid-polyketide hybrid natural products.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/jacs.1c13074 | DOI Listing |
Environ Res
August 2025
School of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi'an, 710021, PR China. Electronic address:
Nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) are contaminants of emerging concern due to their various sources and widespread existence in the environment. This study demonstrated an in-depth comparison of the aqueous and ice photochemistry of three nitro-PAHs: 1-nitropyrene (1-Npyr), 2-nitrofluorene (2-Nflu) and 9-nitrophenanthrene (9-Nphe). Upon exposure to the simulating solar irradiation (λ > 290 nm), their apparent photolysis followed pseudo-first-order kinetics, with apparent quantum yields (Φ) and half-lives (t) depending on the chemical structures or the reaction media (water/ice).
View Article and Find Full Text PDFJ Am Chem Soc
March 2022
Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, JAPAN.
Pyridoxal 5'-phosphate (PLP)-dependent enzymes are a group of versatile enzymes that catalyze various reactions, but only a small number of them react with O. Here, we report an unprecedented PLP-dependent enzyme, NphE, that catalyzes both transamination and two-electron oxidation using O as an oxidant. Our intensive analysis reveals that NphE transfers the l-glutamate-derived amine to 1,3,6,8-tetrahydroxynaphthalene-derived mompain to form 8-amino-flaviolin (8-AF) via a highly conjugated quinonoid intermediate that is reactive with O.
View Article and Find Full Text PDFJ Agric Food Chem
October 2017
School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China.
The transpeptidase activity of glutaminase from Bacillus amyloliquefaciens (GBA) and Aspergillus oryzae (GAO) to yield γ-[Glu]-Phe peptides were verified for the first time. In the presence of Gln and Phe, γ-Glu-Phe and γ-Glu-γ-Glu-Phe were synthesized by GAO, and γ-Glu-Phe, γ-Glu-γ-Glu-Phe, γ-Glu-γ-Glu-γ-Glu-Phe, γ-Glu-γ-Glu-γ-Glu-γ-Glu-Phe, and γ-Glu-γ-Glu-γ-Glu-γ-Glu-γ-Glu-Phe were synthesized by GBA. The K values for the transpeptidation catalyzed by GBA and GAO were 47.
View Article and Find Full Text PDFEur J Pharm Sci
June 2017
Institute of Pharmacology, Department of Pain Pharmacology, Krakow, Poland. Electronic address:
A bifunctional peptide containing an opioid and nociceptin receptor-binding pharmacophore, H-Dmt-D-Arg-Aba-β-Ala-Arg-Tyr-Tyr-Arg-Ile-Lys-NH2 (KGNOP1), was tested for its analgesic properties when administered intrathecally in naïve and chronic constriction injury (CCI)-exposed rats with neuropathy-like symptoms. KGNOP1 significantly increased the acute pain threshold, as measured by the tail-flick test, and also increased the threshold of a painful reaction to mechanical and thermal stimuli in CCI-exposed rats. Both of the effects could be blocked by pre-administration of [Nphe1]-Nociceptin (1-13)-NH (NPhe) or naloxone, antagonists for nociceptin and opioid receptors, respectively.
View Article and Find Full Text PDFWorld J Gastrointest Pharmacol Ther
August 2015
Andrei Sibaev, Birol Yuece, Martin Storr, Department of Medicine, Division of Gastroenterology, Ludwig Maximilians University of Munich, 81377 Munich, Germany.
Aim: To study the effect of the opioid-receptor like-1 (ORL1) agonist nociceptin on gastrointestinal (GI) myenteric neurotransmission and motility.
Methods: Reverse transcriptase - polymerase chain reaction and immunohistochemistry were used to localize nociceptin and ORL1 in mouse tissues. Intracellular electrophysiological recordings of excitatory and inhibitory junction potentials (EJP, IJP) were made in a chambered organ bath.