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This paper reports novel hybrid arborescent polypeptides based on poly(γ-benzyl l-glutamate)

In this paper, a peroxyoxalate chemiluminescence (CL) recovery system based on the interaction of N-doped graphene oxide nanosheets (N-GONs) and an oligopeptide for copper(II) ion detection has been reported. N-GONs as an excellent CL enhancer are prepared by the hydrothermal method using citric acid and ammonia, and the morphology and structure are characterized in detail by TEM, XPS, FT-IR and UV/vis

Macropinocytosis mediates non-selective bulk uptake of extracellular fluid. It is the major route by which axenic Dictyostelium cells obtain nutrients and has emerged as a nutrient-scavenging pathway in mammalian cells. How environmental and cellular nutrient status modulates macropinocytic activity is not well understood. By developing a high-content imaging-based genetic screen in Dictyostelium discoideum we identified Slc15A, an oligopeptide transporter located at the plasma membrane and early macropinosome, as a novel macropinocytosis regulator. We show that deletion of slc15A but not two other related slc15 genes, leads to reduced macropinocytosis, reduced cell growth and aberrantly increased autophagy in cells grown in nutrient-rich medium. Expression of Slc15A protein or supplying cells with free amino acids rescues these defects. In contrast, expression of transport-defective Slc15A or supplying cells with amino acids in their di-peptide forms fails to rescue these defects. Therefore, Slc15A modulates the level of macropinocytosis by maintaining the intracellular availability of key amino acids through extraction of oligopeptides from the early macropinocytic pathway. We propose that Slc15A constitutes part of a positive feedback mechanism coupling cellular nutrient status and macropinocytosis. This article has an associated First Person interview with the first authors of the paper.

Using Protein Data Bank (PDB), the distribution of backbone torsional angle for dipeptides and tripeptides has been obtained and analyzed in several past works. However, the more extended peptides distributions are difficult to obtain due to the data sparsity. In this paper, we introduce a technique based on Optimal Transport theory to understand peptide conformations. This technique renders a computational method to determine the multi-point distribution of the backbone torsional angles of the peptide. Applying this technique, we study tetrapeptide conformations, presenting a detailed analysis of tetrapeptides distributions composed of Ala and Gly amino acids, and compare it with PDB data. Our study shows that tetrapeptides such as AAAA, AAAG, AGAA, and GAAA prefer right-handed alpha-helix secondary structure formations and beta-turns in GGGG, GAGG, AAGG, and AAGA.