1.
Trypsin Binding with Copper Ions Scavenges Superoxide: Molecular Dynamics-Based Mechanism Investigation.
Li, X, Zhong, Y, Zhao, C
International journal of environmental research and public health. 2018;(1)
Abstract
Trypsin is a serine protease, which has been proved to be a novel superoxide scavenger. The burst of superoxide induced by polychlorinated biphenyls can be impeded by trypsin in both wild type and sod knockout mutants of Escherichia coli. The experimental results demonstrated that the activities of superoxide scavenging of trypsin were significantly accelerated by Cu ions. Also, with the addition of Cu ions, a new β-sheet (β7) transited from a random coil in the Cu(II)-trypsin (TP) system, which was favorable for the formation of more contacts with other sheets of trypsin. Residue-residue network analysis and the porcupine plots proved that the Cu ion in trypsin strengthened some native interactions among residues, which ultimately resulted in much greater stability of the Cu(II)-TP system. Moreover, compact and stable trypsin structures with Cu ions might be responsible for significantly provoking the activity of superoxide scavenging.
2.
Antibacterial anthraquinone derivatives isolated from a mangrove-derived endophytic fungus Aspergillus nidulans by ethanol stress strategy.
Yang, SQ, Li, XM, Xu, GM, Li, X, An, CY, Wang, BG
The Journal of antibiotics. 2018;(9):778-784
Abstract
Three new natural products, including a new anthraquinone derivative isoversicolorin C (1), a new xanthone analog isosecosterigmatocystin (2), and a new amino acid derivative, glulisine A (3), along with six related metabolites (4-9) were isolated from the culture broth and mycelia extracts of the mangrove-derived endophytic fungus Aspergillus nidulans MA-143 under 0.1% ethanol stress. Their structures were elucidated by detailed analysis of their NMR spectra, ECD spectrum, and X-ray crystallographic experiments. Compounds 1 and 4 showed potent antibacterial activity against some of the tested microbes.