Undecapeptide with antibacterial activity
By designing an undecapeptide with an amino-terminal -AKKLLKWVKKK-carboxyl-terminal amino acid sequence, the problem of insufficient antioxidant activity of existing antimicrobial peptides has been solved, achieving highly efficient antimicrobial and antioxidant effects, which is applicable to the field of peptide biotechnology.
Patent Information
- Application Number
- CN202511202721.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-22
- Publication Date
- 2025-12-12
AI Technical Summary
Few existing antimicrobial peptides have antioxidant properties, making it difficult to effectively scavenge free radicals and reduce oxidative stress damage to cells.
An undecyl peptide with an amino-terminal -AKKLLKWVKKK-carboxyl-terminal amino acid sequence was designed and prepared by solid-phase synthesis. Its minimum inhibitory concentration and ABTS radical scavenging ability were determined, demonstrating highly efficient antibacterial and antioxidant activities.
This peptide exhibited antibacterial activity of 1024 μg/mL against a variety of bacteria in the minimum inhibitory concentration assay, and had an IC50 value of 11.06 μg/mL in the ABTS free radical scavenging assay, demonstrating excellent antioxidant properties and reducing oxidative stress damage to cells.
Smart Images
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Abstract
Description
Technical fields:
[0001] This invention relates to the field of peptide biotechnology, and in particular to an undecapeptide with antibacterial activity. Background technology:
[0002] Antibacterial peptides (ABPs), also known as antimicrobial peptides, originally referred to a class of basic polypeptides with a molecular weight of around 4 kDa that are induced to be produced in insects and possess antibacterial activity. They were first discovered in 1972 by Swedish scientist Boman in the cecropia silkworm and named cecropins. Subsequently, scientists isolated polypeptides with broad-spectrum antibacterial and antimicrobial activities from various organisms, thus expanding the concept of antibacterial peptides to include polypeptides with antibacterial activity present in organisms. In addition to antiviral, antibacterial, and antifungal functions, some AMPs have been found to have strong antioxidant functions and free radical scavenging effects. However, the number of antimicrobial peptides with antioxidant activity reported so far is relatively small. Summary of the Invention:
[0003] This invention provides an undecapeptide with antibacterial activity, characterized by its amino acid sequence: amino-terminal -AKKLLKWVKKK-carboxyl-terminal. This peptide not only effectively inhibits the growth of various bacteria, exhibiting excellent antibacterial activity, but also possesses certain antioxidant properties, capable of scavenging free radicals and reducing oxidative stress-induced cell damage. Attached image description:
[0004] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will now be described in further detail with reference to the accompanying drawings, wherein:
[0005] Figure 1 This is a graph showing the ABTS free radical scavenging ability of AKKLLKWVKKK. Detailed implementation method:
[0006] The peptide of this invention was synthesized by solid-phase synthesis, and its amino acid sequence is: amino-terminal-AKKLLKWVKKK-carboxyl-terminal.
[0007] Antibacterial activity was determined using the minimum inhibitory concentration (MIC) assay. The specific procedure is as follows: First, prepare a fresh bacterial culture. Then, measure the OD600 value of the culture using a UV spectrophotometer, and follow the formula OD600 = 1 × 10⁻⁶. 8 The standard CFU / ml is used to dilute the bacterial culture to 2×10⁻⁶. 5CFU / ml. Then, 100 μl of physiological saline was added to a sterile 96-well plate, and the sample to be tested was added to the first well. This was followed by a two-fold serial dilution, with 100 μl of a 2×10⁻⁶ concentration added to each well. 5 The bacterial culture was prepared at CFU / ml and mixed thoroughly with a pipette. The 96-well plate was incubated overnight at 37°C. The next day, the absorbance at 600 nm was measured in each well using a microplate reader. By comparing the OD600 values of different wells, the minimum inhibitory concentration (MIC), i.e., the lowest concentration that can completely inhibit bacterial growth, was determined.
[0008] As shown in Table 1, the MIC values of this peptide against four bacteria—Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa—were all 1024 μg / mL in the minimum inhibitory concentration assay, indicating that the peptide has high antibacterial activity.
[0009] Table 1. MIC values of antimicrobial peptides AKKLLKWVKKK against different bacterial strains.
[0010]
[0011] The antioxidant activity of ABTS was assessed using its IC50 value as an antioxidant index. The determination process for ABTS free radical scavenging ability was as follows: ABTS was mixed with potassium persulfate solution at a 1:1 ratio and incubated in the dark for 12 hours to generate ABTS free radical cations. The mixture was then diluted with phosphate buffer (pH = 6.6) to adjust the absorbance at 734 nm to 0.7 ± 0.2. 0.2 mL of sample solutions of different concentrations was mixed with 2 mL of ABTS working solution and reacted in the dark at room temperature for 6 minutes. The absorbance (As) was measured at 734 nm. Simultaneously, a blank experiment was conducted using phosphate buffer instead of the ABTS working solution to determine its absorbance (Ab), and a control experiment was conducted using distilled water instead of the sample solution to determine its absorbance (Ac). The ABTS free radical scavenging rate was calculated using the following formula:
[0012]
[0013] Where: Ac - absorbance of the control group;
[0014] As-sample group absorbance
[0015] Ab - Absorbance of the blank group.
[0016] from Figure 1 It can be concluded that the IC50 value of this peptide in the ABTS free radical scavenging experiment is 11.06 μg / mL, indicating that the peptide has high antioxidant activity. Its amino acid sequence is: amino-terminal-AKKLLKWVKKK-carboxyl-terminal.
[0017] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.
Claims
1. An undecapeptide with antibacterial activity, characterized in that... Its amino acid sequence is: amino-terminal -AKKLLKWVKKK-carboxyl-terminal.