LAH4 peptide

• Handling and Storage of Synthetic Peptides
• Material Safety Data Sheets (MSDS)

Batch to batch variation of the purity

LAH4 is a 26-residue peptide that adopts an amphipathic α-helical conformation upon association with lipid bilayers. At pH 7.5, it assumes a transmembrane orientation with lysine residues at each terminus acting as hydrophilic anchors, while at acidic pH, it switches to an in-plane orientation due to the protonation of its four histidine residues. Solid-state NMR studies demonstrate that LAH4 preferentially interacts with anionic lipids such as phosphatidylserine (PS) and phosphatidylglycerol (PG) in mixed model membranes, with stronger interactions observed at acidic pH. Additionally, ²H NMR reveals that LAH4 effectively disrupts the acyl chains of anionic lipids at low pH, indicating its ability to destabilize lipid bilayers under acidic conditions.

The interaction between LAH4 and anionic lipids is influenced by the spatial arrangement of its histidine residues. Peptide isomers with specific angles (80° and 100°) exhibit higher lipid-disrupting efficiency, as measured by ²H NMR, compared to those with angles of 60° and 180°. This structural dependency correlates with the peptide's functional activity in model membranes, highlighting the importance of anionic lipid interactions in LAH4's membrane-disrupting properties.

• Mason AJ, Martinez A, Glaubitz C, Danos O, Kichler A, Bechinger B. The antibiotic and DNA-transfecting peptide LAH4 selectively associates with, and disorders, anionic lipids in mixed membranes. FASEB J. 2006 Feb;20(2):320-2. doi: 10.1096/fj.05-4293fje. Epub 2005 Dec 13. PMID: 16352649.

Trifluoroacetic acid (TFA) is a common counterion from the purification process using High-Performance Liquid Chromatography (HPLC). The presence of TFA can affect the peptide's net weight, appearance, and solubility.

Impact on Net Weight: The TFA salt contributes to the total mass of the product. In most cases, the peptide content constitutes >80% of the total weight, with TFA accounting for the remainder.

Solubility: TFA salts generally enhance the solubility of peptides in aqueous solutions.

In Biological Assays: For most standard in vitro assays, the residual TFA levels do not cause interference. However, for highly sensitive cellular or biochemical studies, please be aware of its presence.