L5K5W peptide

L5K5W peptide

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

KKLLKWLKKLL

Lys-Lys-Leu-Leu-Lys-Trp-Leu-Lys-Lys-Leu-Leu

11

96.3%

Synthetic

Powder

A prototype de novo design of amphipathic helix involves only Lys and Leu residues (i.e. LK-peptides). Systematic studies revealed that 14-15 such residues are required to form a helical peptide that is active against bacteria (Blondelle SE & Houghten RA 1992 Biochemistry 31:12688-94). Shorter peptides are inactive, while longer peptides tend to be hemolytic. This 11mer peptide is only active after inserting an Trp, a well-known membrane anchor (see Chapter 4, Wang, G. ed. 2010 Antimicrobial peptides: discovery, design and novel therapeutic strategies, CABI). Remarkably, Shai and colleagues demonstrated (Animal model:mouse) the systemic effect of an KL-peptide, K6L9, seq LKLLKKLLKKLLKLL-NH2, consisting of a mixture of L, D-amino acids, that cures neutropenic mice infected with gentamicin-sensitive Pseudomonas aeruginosa and gentamicin-resistant Acinetobacter baumannii Gram-negative pathogenic bacteria (Braustein A et al 2004 Antimicrob Agents Chemother 48:3127-9). 9/2010; 9/2011 GW. L5K5W has Antimicrobial activity. L5K5W was found in de novo design.

Normally, this peptide will be delivered in lyophilized form and should be stored in a freezer at or below -20 °C. For more details, please refer to the manual:Handling and Storage of Synthetic Peptides

• Kang SJ, Won HS, Choi WS, Lee BJ. De novo generation of antimicrobial LK peptides with a single tryptophan at the critical amphipathic interface. J Pept Sci. 2009;15(9):583-8.

Trifluoroacetic acid (TFA) has a significant impact on peptides due to its role in the peptide synthesis process.

TFA is essential for the protonation of peptides that lack basic amino acids such as Arginine (Arg), Histidine (His), and Lysine (Lys), or ones that have blocked N-termini. As a result, peptides often contain TFA salts in the final product.

TFA residues, when present in custom peptides, can cause unpredictable fluctuations in experimental data. At a nanomolar (nM) level, TFA can influence cell experiments, hindering cell growth at low concentrations (as low as 10 nM) and promoting it at higher doses (0.5–7.0 mM). It can also serve as an allosteric regulator on the GlyR of glycine receptors, thereby increasing receptor activity at lower glycine concentrations.

In an in vivo setting, TFA can trifluoroacetylate amino groups in proteins and phospholipids, inducing potentially unwanted antibody responses. Moreover, TFA can impact structure studies as it affects spectrum absorption.