Q53 CecB (Cecropin B) peptide

Q53 CecB (Cecropin B) peptide

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

H-AGWLRKLGKKIQRIGQHTRDASIQVLGIAQQAANVAATAR-NH2

H-Ala-Gly-Trp-Leu-Arg-Lys-Leu-Gly-Lys-Lys-Ile-Gln-Arg-Ile-Gly-Gln-His-Thr-Arg-Asp-Ala-Ser-Ile-Gln-Val-Leu-Gly-Ile-Ala-Gln-Gln-Ala-Ala-Asn-Val-Ala-Ala-Thr-Ala-Arg-NH2

40

95.2%

C₁₈₇H₃₂₁N₆₅O₅₁

4295.93

Synthetic

Powder

These cecropin B isoforms differ in a single amino acid substitution within the active portion of the peptide, so that the glutamic acid of the E53 CecB variant is replaced by a glutamine in the Q53 CecB isoform. Both peptides showed a high antimicrobial and membranolytic activity against P. aeruginosa, with Q53 CecB displaying greater activity compared with the E53 CecB isoform. Biophysical analyses, live-cell NMR, and moleculardynamic-simulation studies indicated that both peptides might act as membrane-interacting elements, which can disrupt outermembrane organization, facilitating their translocation toward the inner membrane of the bacterial cell. Our data also suggest that the amino acid variation of the Q53 CecB isoform represents a critical factor in stabilizing the hydrophobic segment that interacts with the bacterial membrane, determining the highest antimicrobial activity of the whole peptide. Its high stability to pH and temperature variations, tolerance to high salt concentrations, and low toxicity against human cells make Q53 CecB a promising candidate in the development of CecB-derived compounds against P. aeruginosa.

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

• Romoli O, Mukherjee S, Mohid SA, et al. Enhanced Silkworm Cecropin B Antimicrobial Activity against Pseudomonas aeruginosa from Single Amino Acid Variation. ACS Infect Dis. 2019;5(7):1200-1213. doi:10.1021/acsinfecdis.9b00042

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.