Editorial: Current trends in peptide science

Abstract

This “Current Trends in Peptide Science” issue features papers broadly based on the diversity of biologically-important interactions of peptides and proteins with cellular membranes. In the first paper, Unson focuses on the seven-helix transmembrane receptor for glucagon, a 29-residue peptide hormone that functions to counterbalance the effects of insulin in blood glucose levels. She describes progress toward the elucidation of molecular determinants of ligand specificity by the receptor, itself a member of the G-protein coupled receptor (GPCR) family, and discusses models which have been proposed for the specificity of binding of these so-called Family B receptors to a series of highly homologous peptide ligands. Noting the increasing resistance of bacteria to conventional antibiotics, Shai then presents an in-depth discussion of a new generation of antibiotic peptides. Because these peptides are active across a wide range of lengths and sequences, he presents evidence for the “carpet model” of peptide antibiotic action—a generalized mechanism for bacterial membrane binding and penetration which may be coupled in some instances with eventual targeting of the peptides to the cytoplasmic region of the organism. In a related theme, Tamm presents a review of membrane fusion peptides that are constituted of highly conserved hydrophobic segments of fusion proteins; these peptides which mediate processes requiring two cellular membranes to fuse into one. Focusing on influenza hemagglutinin fusion peptides, Tamm describes biophysical approaches—including NMR spectroscopy. ATR infrared techniques, and differential scanning calorimetry—to deduction of the structures and interactions of these peptides with phospholipid bilayers. McCafferty and his co-workers conclude this issue with a discussion of the wide-ranging properties of the peptide antibiotic ramaplanin family—compounds structurally related to cell wall-active lipodepsipeptides—which may find clinical use against vancomycin-resistant and methicillin-resistant pathogens. The collection of papers in this issue truly reflects the important advances in our understanding of peptide/protein interactions with membranes—whether involving receptor-mediated recognition, surface binding, membrane penetration/fusion, or mechanisms of antibiotic action—as well as highlighting the momentum for continuing research in these emerging fields.