[EN] COMPOUNDS TARGETING RNA-BINDING PROTEINS OR RNA-MODIFYING PROTEINS [FR] COMPOSÉS CIBLANT DES PROTÉINES DE LIAISON À L'ARN OU DES PROTÉINES MODIFIANT L'ARN
Ternary Nylon-3 Copolymers as Host-Defense Peptide Mimics: Beyond Hydrophobic and Cationic Subunits
摘要:
Host-defense peptides (HDPs) are produced by eukaryotes to defend against bacterial infection, and diverse synthetic polymers have recently been explored as mimics of these natural peptides. HDPs are rich in both hydrophobic and cationic amino acid residues, and most HDP-mimetic polymers have therefore contained binary combinations of hydrophobic and cationic subunits. However, HDP-mimetic polymers rarely duplicate the hydrophobic surface and cationic charge density found among HDPs (Hu , K.; et al. Macromolecules 2013 , 46 , 1908); the charge and hydrophobicity are generally higher among the polymers. Statistical analysis of HDP sequences (Wang , G.; et al. Nucleic Acids Res. 2009 , 37 , D933) has revealed that serine (polar but uncharged) is a very common HDP constituent and that glycine is more prevalent among HDPs than among proteins in general. These observations prompted us to prepare and evaluate ternary nylon-3 copolymers that contain a modestly polar but uncharged subunit, either serine-like or glycine-like, along with a hydrophobic subunit and a cationic subunit. Starting from binary hydrophobic-cationic copolymers that were previously shown to be highly active against bacteria but also highly hemolytic, we found that replacing a small proportion of the hydrophobic subunit with either of the polar, uncharged subunits can diminish the hemolytic activity with minimal impact on the antibacterial activity. These results indicate that the incorporation of polar, uncharged subunits may be generally useful for optimizing the biological activity profiles of antimicrobial polymers. In the context of HDP evolution, our findings suggest that there is a selective advantage to retaining polar, uncharged residues in natural antimicrobial peptides.
β-Lactams. XI. Synthesis of <i>N</i>-phosphorylated mono- and bicyclic β-lactams
作者:George Just、Denise Dugat、Whi-Yu Liu
DOI:10.1139/v83-296
日期:1983.8.1
Starting from appropriately.substituted monocyclic β-lactam, N-phosphorylated mono- and bicyclic β-lactams have been synthesized.
从适当替代的单环β-内酰胺出发,已合成了N-磷酸化的单环和双环β-内酰胺。
Tethered Aminohydroxylation (TA) Reaction of Amides
作者:Timothy J. Donohoe、Cedric K. A. Callens、Amber L. Thompson
DOI:10.1021/ol900631y
日期:2009.6.4
The first examples of amide-tethered aminohydroxylationreactions, catalyzed by osmium, showing that the use of N−O-based reoxidants are essential for success, are reported. The system that is described is compatible with a variety of different alkene substitution patterns and ring sizes and works with low loadings in both cyclic and acyclic systems. The levels of diastereoselectivity that were observed