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Strain HT88 was isolated from the fresh stems of , and it was identified as sp. by analyzing its morphology and the 16S rRNA sequence. The extracts of fermented HT88 showed potent antimicrobial activities. Bioassay guided separation of extracts led to eight proline -containing cyclic dipeptides. Their structures were determined by 1D and 2D NMR spectroscopy and ESI mass spectrometry and further comparison with existing H and C NMR, melting points and specific rotation data. The eight 2,5-diketopiperazines (DKPs) were identified as cyclo(-Pro-Leu) (), cyclo(Pro-Leu) (), cyclo(--Hyp--Leu) (), cyclo(--Hyp--Leu) (), and cyclo(-Pro--Phe) (), cyclo(-Pro--Phe) (, and cyclo(--Hyp--Phe) (), cycloHyp-Phe) (), respectively. Up to date, this is the first isolation of four pairs of proline based DKPs from sp.
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http://dx.doi.org/10.1080/14786419.2019.1577834 | DOI Listing |
Phys Chem Chem Phys
August 2025
A. M. Butlerov Institute of Chemistry, Kazan Federal University, Kremlevskaya 18, Kazan, 420008, Russia.
New biocompatible luminescent materials based on cyclic dipeptides were prepared. For this, the thermal properties of dipeptides L-alanyl-L-leucine and L-leucyl-L-alanine and the kinetics of their cyclization in the solid-state upon heating are studied for the first time. Using isoconversion kinetics approaches, the kinetic parameters of the reactions and the models describing these processes are determined.
View Article and Find Full Text PDFProtein Sci
September 2025
Institute of Bioorganic Chemistry & Bioeconomy Science Center (BioSC), Heinrich Heine University Düsseldorf in Forschungszentrum Jülich, Jülich, Germany.
The pyrroloindole (hexahydropyrrolo[2,3-b]indole, HPI) structural motif is present in a wide range of natural products with various biological activities, yet its chemical synthesis poses a challenge, particularly regarding methylation at the indole C3 position. In nature, S-adenosyl methionine (SAM)-dependent methyltransferases efficiently catalyze this reaction with high stereoselectivity. This study presents the investigation and rational re-design of a potential methyltransferase, termed SeMT, from the actinomycete Saccharopolyspora erythraea.
View Article and Find Full Text PDFPhotochem Photobiol
August 2025
Nippi Research Institute of Biomatrix, Toride, Ibaraki, Japan.
Reactive oxygen species (ROS) are major contributors to skin photoaging, which is cumulatively caused by sunlight exposure. We previously developed a unique collagen hydrolysate, named H-GDCH, enriched with hydroxyproline (Hyp)-containing cyclic dipeptides, cyclo(X-Hyp), using ginger protease and subsequent heat treatment. Here, we demonstrated the inhibitory effects of cyclo(X-Hyp) and H-GDCH on ultraviolet B (UVB)-induced photoaging-related inflammatory response in normal human epidermal keratinocytes (NHEK).
View Article and Find Full Text PDFCurr Res Microb Sci
July 2025
Research Organization of Earth Sciences and Maritime, National Research and Innovation Agency (BRIN), Jakarta, Indonesia.
Marine-associated bacteria serve as a significant source of bioactive natural products for drug discovery efforts. The microbial symbionts of heterobranchs and their prey represent a promising source of bioactive compounds with potential applications as pharmaceutical agents. This study aimed to evaluate the diversity of associated microbes of heterobranchs and their prey that were obtained from one of marine biodiversity hotspots.
View Article and Find Full Text PDFEur J Med Chem
November 2025
Institute of Biostructure and Bioimaging, CNR, via P. Castellino, 111, 80131, Naples, Italy. Electronic address:
The formation of the Tissue Factor(TF):Factor VII(FVII) complex is a pivotal event that initiates coagulation; targeting this early step allows for the prevention of the subsequent cascade amplification driven by positive feedback loops. For this reason, the TF:FVII complex is attracting increasing interest as a potential therapeutic target for regulating the coagulation cascade in a specific and timely manner. In order to generate TF-mimics capable of inhibiting this protein-protein interaction, we have designed four small cyclic peptides that simulate a TF region containing the two antiparallel β-strands: 106-110 (RVFSY) and 123-128 (EPLYEN).
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