RW4 peptide

• COA/MS/HPLC Report
• Handling and Storage of Synthetic Peptides
• Material Safety Data Sheets (MSDS)

Batch to batch variation of the purity

The RW4 peptide, part of the (RW)_n series, is a synthetic cationic antimicrobial peptide composed of four repeats of arginine (R) and tryptophan (W) residues, with a C-terminal amidation. This peptide exhibits a strong interaction with negatively charged phospholipid bilayers, such as those containing phosphatidylglycerol (POPG), as demonstrated by circular dichroism spectroscopy and tryptophan fluorescence studies. The RW4 peptide shows enhanced antimicrobial activity with increasing chain length, attributed to its ability to partition into lipid membranes and disrupt bilayer integrity. Spectroscopic data indicate that RW4 undergoes conformational changes upon binding to lipid vesicles, suggesting a mechanism involving membrane intercalation.

Fluorescence studies reveal that the tryptophan residues in RW4 are more protected in POPG vesicles compared to zwitterionic phosphatidylcholine (POPC) vesicles, highlighting its preferential interaction with negatively charged membranes. The peptide's antimicrobial efficacy correlates with its chain length, with longer peptides like RW4 demonstrating greater activity. These findings underscore the importance of arginine and tryptophan residues in mediating peptide-lipid interactions and membrane disruption, providing insights into the design of short, potent antimicrobial peptides.

• Strøm et al (2002) Antimicrobial activity of short arginine- and tryptophan-rich peptides. J. Pept. Sci. 8(8) 431 PMID: 12212806
• Liu et al (2007) Length effects in antimicrobial peptides of the (RW)n series. Antimicrob. Agents Chemother. 51(2) 597 PMID: 17145799
• Mohan et al (2014) Enhanced antimicrobial activity of peptide-cocktails against common bacterial contaminants of ex vivo stored platelets. Clin. Microbiol. Infect. 20(1) O39 PMID: 23926880

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.