4 research outputs found
Althusser and the Critique of Political Economy
Two disulfide-containing peptides,
barrettides A (<b>1</b>) and B (<b>2</b>), from the cold-water
marine sponge <i>Geodia barretti</i> are described. Those
31 amino acid residue
long peptides were sequenced using mass spectrometry methods and structurally
characterized using NMR spectroscopy. The structure of <b>1</b> was confirmed by total synthesis using the solid-phase peptide synthesis
approach that was developed. The two peptides were found to differ
only at a single position in their sequence. The three-dimensional
structure of <b>1</b> revealed that these peptides possess a
unique fold consisting of a long Ī²-hairpin structure that is
cross-braced by two disulfide bonds in a ladder-like arrangement.
The peptides are amphipathic in nature with the hydrophobic and charged residues clustered on separate
faces of the molecule. The barrettides were found not to inhibit the
growth of either <i>Escherichia coli</i> or <i>Staphylococcus
aureus</i> but displayed antifouling activity against barnacle
larvae (<i>Balanus improvisus</i>) without lethal effects
in the concentrations tested
Stabilized Cyclic Peptides as Scavengers of Autoantibodies: Neutralization of Anticitrullinated Protein/Peptide Antibodies in Rheumatoid Arthritis
The
occurrence of autoantibodies is a hallmark of rheumatoid arthritis,
specifically those autoantibodies targeting proteins containing the
arginine-derived amino acid citrulline. There is strong evidence showing
that the occurrence of anticitrullinated protein/peptide antibodies
(ACPA) are involved in disease progression, and ACPA was recently
shown to induce pain in animals. Here, we explore a novel concept
useful for research, diagnostics, and possibly therapy of autoimmune
diseases, namely, to directly target and neutralize autoantibodies
using peptide binders. A high-affinity peptide-based scavenger of
ACPA was developed by grafting a citrullinated epitope derived from
human fibrinogen into a naturally occurring stable peptide scaffold.
The best scavenger comprises the truncated epitope Ī±-fibrinogen,
[Cit573]Āfib(566ā580), grafted into the scaffold sunflower trypsin
inhibitor-1, SFTI-1. The final peptide demonstrates low nanomolar
apparent affinity and superior stability
The āPepSAVI-MSā Pipeline for Natural Product Bioactive Peptide Discovery
The
recent increase in extensively drug-resistant bacterial pathogens
and the associated increase of morbidity and mortality demonstrate
the immediate need for new antibiotic backbones with novel mechanisms
of action. Here, we report the development of the PepSAVI-MS pipeline
for bioactive peptide discovery. This highly versatile platform employs
mass spectrometry and statistics to identify bioactive peptide targets
from complex biological samples. We validate the use of this platform
through the successful identification of known bioactive peptides
from a botanical species, Viola odorata. Using this pipeline, we have widened the known antimicrobial spectrum
for V. odorata cyclotides, including
antibacterial activity of cycloviolacin O2 against A.Ā baumannii. We further demonstrate the broad
applicability of the platform through the identification of novel
anticancer activities for cycloviolacins by their cytotoxicity against
ovarian, breast, and prostate cancer cell lines