Functional Assay to Correlate Protein Oligomerization States with Membrane Pore Formation.

In-membrane oligomerization is decisive for the function (or dysfunction) of many proteins. Techniques were developed to characterize membrane-inserted oligomers and the hereby obtained oligomerization states were intuitively related to the function of these proteins. However, in many cases, it is unclear whether the obtained oligomerization states are functionally relevant or are merely the consequence of nonspecific aggregation.

Key steps in unconventional secretion of fibroblast growth factor 2 reconstituted with purified components.

FGF2 is secreted from cells by an unconventional secretory pathway. This process is mediated by direct translocation across the plasma membrane. Here, we define the minimal molecular machinery required for FGF2 membrane translocation in a fully reconstituted inside-out vesicle system.

Conformational study of melectin and antapin antimicrobial peptides in model membrane environments.

Antimicrobial peptides have long been considered as promising compounds against drug-resistant pathogens. In this work, we studied the secondary structure of antimicrobial peptides melectin and antapin using electronic (ECD) and vibrational circular dichroism (VCD) spectroscopies that are sensitive to peptide secondary structures. The results from quantitative ECD spectral evaluation by Dichroweb and CDNN program and from the qualitative evaluation of the VCD spectra were compared.

Interaction of a novel antimicrobial peptide isolated from the venom of solitary bee Colletes daviesanus with phospholipid vesicles and Escherichia coli cells.

The peptide named codesane (COD), consisting of 18 amino acid residues and isolated from the venom of wild bee Colletes daviesanus (Hymenoptera : Colletidae), falls into the category of cationic α-helical amphipathic antimicrobial peptides. In our investigations, synthetic COD exhibited antimicrobial activity against Gram-positive and Gram-negative bacteria and Candida albicans but also noticeable hemolytic activity. COD and its analogs (collectively referred to as CODs) were studied for the mechanism of their action.

Structural basis for antimicrobial activity of lasiocepsin.

Lasiocepsin is a unique 27-residue antimicrobial peptide, isolated from Lasioglossum laticeps (wild bee) venom, with substantial antibacterial and antifungal activity. It adopts a well-defined structure consisting of two α-helices linked by a structured loop. Its basic residues form two distinct positively charged regions on the surface whereas aliphatic side chains contribute to solvent-accessible hydrophobic areas, thus emphasising the amphipathic character of the molecule.

Panurgines, novel antimicrobial peptides from the venom of communal bee Panurgus calcaratus (Hymenoptera: Andrenidae).

Three novel antimicrobial peptides (AMPs), named panurgines (PNGs), were isolated from the venom of the wild bee Panurgus calcaratus. The dodecapeptide of the sequence LNWGAILKHIIK-NH₂ (PNG-1) belongs to the category of α-helical amphipathic AMPs. The other two cyclic peptides containing 25 amino acid residues and two intramolecular disulfide bridges of the pattern Cys8-Cys23 and Cys11-Cys19 have almost identical sequence established as LDVKKIICVACKIXPNPACKKICPK-OH (X=K, PNG-K and X=R, PNG-R).